diff --git a/mvp/client/src/generated/index.ts b/mvp/client/src/generated/index.ts
index bd668b7..335638d 100644
--- a/mvp/client/src/generated/index.ts
+++ b/mvp/client/src/generated/index.ts
@@ -9,9 +9,10 @@ export type { OpenAPIConfig } from './core/OpenAPI';
 
 export type { GameSessionDTO } from './models/GameSessionDTO';
 export type { HTTPValidationError } from './models/HTTPValidationError';
-export type { MachineStats } from './models/MachineStats';
+export type { MachineState } from './models/MachineState';
 export type { OperationalParameters } from './models/OperationalParameters';
 export type { ValidationError } from './models/ValidationError';
 
 export { DefaultService } from './services/DefaultService';
+export { MachineInterventionsService } from './services/MachineInterventionsService';
 export { SessionsService } from './services/SessionsService';
diff --git a/mvp/client/src/generated/models/GameSessionDTO.ts b/mvp/client/src/generated/models/GameSessionDTO.ts
index ac64298..4a6e01b 100644
--- a/mvp/client/src/generated/models/GameSessionDTO.ts
+++ b/mvp/client/src/generated/models/GameSessionDTO.ts
@@ -3,10 +3,10 @@
 /* tslint:disable */
 /* eslint-disable */
 
-import type { MachineStats } from './MachineStats';
+import type { MachineState } from './MachineState';
 
 export type GameSessionDTO = {
     id: string;
     current_step: number;
-    machine_stats?: (MachineStats | null);
+    machine_state?: (MachineState | null);
 };
diff --git a/mvp/client/src/generated/models/MachineStats.ts b/mvp/client/src/generated/models/MachineState.ts
similarity index 75%
rename from mvp/client/src/generated/models/MachineStats.ts
rename to mvp/client/src/generated/models/MachineState.ts
index 4f45bfd..f292f9e 100644
--- a/mvp/client/src/generated/models/MachineStats.ts
+++ b/mvp/client/src/generated/models/MachineState.ts
@@ -5,8 +5,8 @@
 
 import type { OperationalParameters } from './OperationalParameters';
 
-export type MachineStats = {
+export type MachineState = {
     predicted_rul?: (number | null);
     health_percentage: number;
-    operational_parameters?: (OperationalParameters | null);
+    operational_parameters: OperationalParameters;
 };
diff --git a/mvp/client/src/generated/services/MachineInterventionsService.ts b/mvp/client/src/generated/services/MachineInterventionsService.ts
new file mode 100644
index 0000000..3f95888
--- /dev/null
+++ b/mvp/client/src/generated/services/MachineInterventionsService.ts
@@ -0,0 +1,34 @@
+/* generated using openapi-typescript-codegen -- do no edit */
+/* istanbul ignore file */
+/* tslint:disable */
+/* eslint-disable */
+import type { GameSessionDTO } from '../models/GameSessionDTO';
+
+import type { CancelablePromise } from '../core/CancelablePromise';
+import { OpenAPI } from '../core/OpenAPI';
+import { request as __request } from '../core/request';
+
+export class MachineInterventionsService {
+
+    /**
+     * Do Maintenance
+     * @param sessionId 
+     * @returns GameSessionDTO Successful Response
+     * @throws ApiError
+     */
+    public static doMaintenanceSessionMachineInterventionsMaintenancePost(
+sessionId: string,
+): CancelablePromise<GameSessionDTO> {
+        return __request(OpenAPI, {
+            method: 'POST',
+            url: '/session/machine/interventions/maintenance',
+            query: {
+                'session_id': sessionId,
+            },
+            errors: {
+                422: `Validation Error`,
+            },
+        });
+    }
+
+}
diff --git a/mvp/client/src/routes/+page.svelte b/mvp/client/src/routes/+page.svelte
index 38aed82..c0b40c8 100644
--- a/mvp/client/src/routes/+page.svelte
+++ b/mvp/client/src/routes/+page.svelte
@@ -1,5 +1,10 @@
 <script lang="ts">
-	import { SessionsService, type GameSessionDTO, OpenAPI } from '../generated';
+	import {
+		SessionsService,
+		type GameSessionDTO,
+		OpenAPI,
+		MachineInterventionsService
+	} from '../generated';
 	import runningMachineSrc from '$lib/assets/healthy.gif';
 
 	const stoppedMachineSrc = new URL('../lib/assets/stopped.PNG', import.meta.url).href;
@@ -7,6 +12,7 @@
 	let gameSession: GameSessionDTO | null;
 	let gameOver = false;
 	let advanceButtonDisabled = false;
+	let maintenanceButtonDisabled = false;
 
 	let stopAnimation = false;
 
@@ -47,6 +53,7 @@
 		// start fetching machine health every second while the day is advancing
 		const intervalId = setInterval(fetchExistingSession, 500);
 		advanceButtonDisabled = true;
+		maintenanceButtonDisabled = true;
 
 		try {
 			gameSession = await SessionsService.advanceSessionTurnsPut(gameSession?.id);
@@ -57,6 +64,24 @@
 			// stop fetching machine health until the player advances to next day again
 			clearInterval(intervalId);
 			advanceButtonDisabled = false;
+			maintenanceButtonDisabled = false;
+		}
+	};
+
+	const doMaintenance = async () => {
+		if (!gameSession || gameOver) {
+			return;
+		}
+
+		try {
+			maintenanceButtonDisabled = true;
+			gameSession =
+				await MachineInterventionsService.doMaintenanceSessionMachineInterventionsMaintenancePost(
+					gameSession?.id
+				);
+		} catch (error) {
+			console.error('Error performing maintenance:', error);
+			maintenanceButtonDisabled = false;
 		}
 	};
 
@@ -65,7 +90,7 @@
 			return;
 		}
 
-		if (gameSession?.machine_stats && gameSession.machine_stats.health_percentage <= 0) {
+		if (gameSession?.machine_state && gameSession.machine_state.health_percentage <= 0) {
 			gameOver = true;
 		}
 	};
@@ -94,6 +119,9 @@
 			<button on:click={advanceToNextDay} disabled={advanceButtonDisabled}
 				>Advance to next day</button
 			>
+			<button on:click={doMaintenance} disabled={maintenanceButtonDisabled}
+				>Perform Maintenance</button
+			>
 		{/if}
 	{:else}
 		<button on:click={startSession}>Start Session</button>
diff --git a/mvp/server/analysis.py b/mvp/server/analysis.py
index 743b1a0..03d2d10 100644
--- a/mvp/server/analysis.py
+++ b/mvp/server/analysis.py
@@ -5,9 +5,9 @@
 
 def compute_decay_speed(parameter_values: 'OperationalParameters') -> float:
     # TODO: calibrate these weights
-    temperature_weight = 0.001
+    temperature_weight = 0.0005
     oil_age_weight = 0.001
-    mechanical_wear_weight = 0.01
+    mechanical_wear_weight = 0.005
 
     # Made-up calculation involving operational parameters:  temperature, oil age, mechanical wear
     computed = parameter_values.temperature * temperature_weight + \
@@ -18,7 +18,9 @@ def compute_decay_speed(parameter_values: 'OperationalParameters') -> float:
                   OIL_AGE_MAPPING_MAX * oil_age_weight + \
                   MECHANICAL_WEAR_MAPPING_MAX * mechanical_wear_weight
 
-    return map_value(computed, from_low=0, from_high=mapping_max, to_low=0, to_high=0.3)
+    computed = min(mapping_max, computed)
+
+    return map_value(computed, from_low=0, from_high=mapping_max, to_low=0, to_high=0.1)
 
 
 def default_rul_prediction_fn(current_timestep: int) -> int | None:
diff --git a/mvp/server/api.py b/mvp/server/api.py
index 306f121..c965899 100644
--- a/mvp/server/api.py
+++ b/mvp/server/api.py
@@ -4,7 +4,7 @@
 from fastapi.middleware.cors import CORSMiddleware
 from starlette.responses import RedirectResponse, JSONResponse
 
-from mvp.server.data_models.GameSession import GameSession, GameSessionDTO
+from mvp.server.core.GameSession import GameSession, GameSessionDTO
 
 app = FastAPI()
 app.add_middleware(
@@ -59,3 +59,15 @@ async def advance(session_id: str) -> GameSessionDTO | JSONResponse:
     await session.advance_one_turn()
 
     return GameSessionDTO.from_session(session)
+
+
+@app.post("/session/machine/interventions/maintenance", response_model=GameSessionDTO, tags=["Machine Interventions"])
+async def do_maintenance(session_id: str) -> GameSessionDTO | JSONResponse:
+    if session_id not in sessions:
+        return JSONResponse(status_code=404, content={"message": "Session not found"})
+
+    session = sessions[session_id]
+
+    session.do_maintenance()
+
+    return GameSessionDTO.from_session(session)
diff --git a/mvp/server/constants.py b/mvp/server/constants.py
index a70c840..a86d139 100644
--- a/mvp/server/constants.py
+++ b/mvp/server/constants.py
@@ -4,4 +4,4 @@
 TEMPERATURE_STARTING_POINT = 20
 OIL_AGE_MAPPING_MAX = 365
 TEMPERATURE_MAPPING_MAX = 200
-MECHANICAL_WEAR_MAPPING_MAX = 1000
+MECHANICAL_WEAR_MAPPING_MAX = 100
diff --git a/mvp/server/data_models/GameSession.py b/mvp/server/core/GameSession.py
similarity index 55%
rename from mvp/server/data_models/GameSession.py
rename to mvp/server/core/GameSession.py
index 83e36e2..90e06d8 100644
--- a/mvp/server/data_models/GameSession.py
+++ b/mvp/server/core/GameSession.py
@@ -5,13 +5,13 @@
 
 from mvp.server.analysis import default_rul_prediction_fn
 from mvp.server.constants import TIMESTEPS_PER_MOVE
-from mvp.server.data_models.MachineState import MachineState
+from mvp.server.core.MachineState import MachineState
 
 
 class GameSession(BaseModel):
     id: str
     current_step: int = 0
-    machine_stats: MachineState
+    machine_state: MachineState
 
     # TODO: Update this function in-game, to simulate a change in the model (an "upgrade" for the player)
     rul_predictor: Callable[[int], int | None] = default_rul_prediction_fn
@@ -21,48 +21,56 @@ def new_game_session(_id: str):
         return GameSession(
             id=_id,
             current_step=0,
-            machine_stats=MachineState.new_machine_stats()
+            machine_state=MachineState.new_machine_state()
         )
 
+    def is_game_over(self) -> bool:
+        if self.machine_state.is_broken():
+            print(f"GameSession '{self.id}' - machine failed at step {self.current_step} - {self.machine_state}")
+            return True
+        # TODO: add other game over conditions, i.e. player ran out of money
+        return False
+
     async def advance_one_turn(self) -> list[MachineState]:
-        collected_machine_stats_during_turn = []
+        collected_machine_state_during_turn = []
 
         for _ in range(TIMESTEPS_PER_MOVE):
             # collect stats
-            collected_machine_stats_during_turn.append(self.machine_stats)
+            collected_machine_state_during_turn.append(self.machine_state)
 
-            # check if game over
-            if self.machine_stats.is_broken():
-                print(f"GameSession '{self.id}' - machine failed at step {self.current_step} - {self.machine_stats}")
+            if self.is_game_over():
                 break
 
             self.current_step += 1
-            self.machine_stats.update_stats_and_parameters(self.current_step, self.rul_predictor)
+            self.machine_state.update_stats_and_parameters(self.current_step, self.rul_predictor)
             self._log()
 
             await asyncio.sleep(0.5)
 
-        return collected_machine_stats_during_turn
+        return collected_machine_state_during_turn
 
     def do_maintenance(self):
-        self.machine_stats.simulate_maintenance()
+        # TODO - add a cost for maintenance, reject if player doesn't have enough money
+        self.machine_state.simulate_maintenance()
 
     def _log(self, multiple=5):
         if self.current_step % multiple == 0:
-            print(f"GameSession '{self.id}' - step: {self.current_step} - {self.machine_stats}")
+            print(f"GameSession '{self.id}' - step: {self.current_step} - {self.machine_state}")
 
 
 class GameSessionDTO(BaseModel):
     id: str
     current_step: int
-    machine_stats: MachineState | None = None
+    machine_state: MachineState | None = None
+
+    # TODO: define MachineStateDTO to hide some fields from the player, e.g. health_percentage
 
     @staticmethod
     def from_session(session: 'GameSession'):
         return GameSessionDTO(
             id=session.id,
             current_step=session.current_step,
-            machine_stats=session.machine_stats,
+            machine_state=session.machine_state,
         )
 
     @staticmethod
@@ -70,5 +78,5 @@ def from_dict(json: dict[str, Any]):
         return GameSessionDTO(
             id=json.get("id", ""),
             current_step=json.get("current_step", 0),
-            machine_stats=MachineState.from_dict(json.get("machine_stats", {}))
+            machine_state=MachineState.from_dict(json.get("machine_state", {}))
         )
diff --git a/mvp/server/data_models/MachineState.py b/mvp/server/core/MachineState.py
similarity index 88%
rename from mvp/server/data_models/MachineState.py
rename to mvp/server/core/MachineState.py
index 163413d..8160daa 100644
--- a/mvp/server/data_models/MachineState.py
+++ b/mvp/server/core/MachineState.py
@@ -4,7 +4,7 @@
 
 from mvp.server.analysis import compute_decay_speed
 from mvp.server.constants import TEMPERATURE_STARTING_POINT
-from mvp.server.data_models.OperationalParameters import OperationalParameters
+from mvp.server.core.OperationalParameters import OperationalParameters
 from mvp.server.math_utils import exponential_decay
 
 
@@ -14,7 +14,7 @@ class MachineState(BaseModel):
     operational_parameters: OperationalParameters
 
     @staticmethod
-    def new_machine_stats():
+    def new_machine_state():
         return MachineState(
             health_percentage=100,
             operational_parameters=OperationalParameters(
@@ -31,11 +31,11 @@ def simulate_maintenance(self):
         self.operational_parameters = OperationalParameters(
             temperature=TEMPERATURE_STARTING_POINT,
             oil_age=0,
-            mechanical_wear=self.operational_parameters.mechanical_wear / 2
+            mechanical_wear=self.operational_parameters.mechanical_wear / 10
         )
-        # TODO: confirm if it makes sense to reset the health percentage; maybe should be kept as is,
+        # TODO: decide if it makes sense to restore some health percentage; maybe should be kept as is,
         #  maintenance does not mean  "new" machine, only slows down the decay
-        # self.health_percentage = 100
+        self.health_percentage = min(100, max(0, round(self.health_percentage * 1.05)))
 
     def update_stats_and_parameters(self, timestep: int, rul_predictor: Callable[[int], int | None] = None):
         self.operational_parameters.update(timestep)
diff --git a/mvp/server/data_models/OperationalParameters.py b/mvp/server/core/OperationalParameters.py
similarity index 91%
rename from mvp/server/data_models/OperationalParameters.py
rename to mvp/server/core/OperationalParameters.py
index 397cb3e..fe0fbc4 100644
--- a/mvp/server/data_models/OperationalParameters.py
+++ b/mvp/server/core/OperationalParameters.py
@@ -34,11 +34,11 @@ def compute_machine_temperature(self, current_timestep: int) -> float:
 
     def compute_oil_age(self, current_timestep: int) -> float:
         # oil age grows monotonically and resets only after every maintenance routine
-        raw_value = self.oil_age + (current_timestep * self.temperature)
+        raw_value = min(1e6, self.oil_age + (current_timestep * self.temperature))
         return map_value(
             raw_value,
             from_low=self.oil_age,
-            from_high=1e5,
+            from_high=1e6,
             to_low=self.oil_age,
             to_high=OIL_AGE_MAPPING_MAX
         )
@@ -46,11 +46,11 @@ def compute_oil_age(self, current_timestep: int) -> float:
     def compute_mechanical_wear(self, current_timestep: int) -> float:
         # mechanical wear grows monotonically, directly proportional to oil ag.
         # for now it never resets (such that at some point, the machine will definitely break and game over)
-        raw_value = math.exp(current_timestep) * self.oil_age / 1e6
+        raw_value = min(1e6, math.exp(current_timestep) * self.oil_age / 1e16)
         return map_value(
             raw_value,
             from_low=0,
-            from_high=1e12,
+            from_high=1e6,
             to_low=self.mechanical_wear,
             to_high=MECHANICAL_WEAR_MAPPING_MAX
         )
diff --git a/mvp/server/data_models/__init__.py b/mvp/server/core/__init__.py
similarity index 100%
rename from mvp/server/data_models/__init__.py
rename to mvp/server/core/__init__.py
diff --git a/mvp/server/tests/test_game_session.py b/mvp/server/tests/test_game_session.py
index cb262b7..afdbf61 100644
--- a/mvp/server/tests/test_game_session.py
+++ b/mvp/server/tests/test_game_session.py
@@ -1,7 +1,7 @@
 import pytest
 
 from mvp.server.constants import TIMESTEPS_PER_MOVE
-from mvp.server.data_models.GameSession import GameSession
+from mvp.server.core.GameSession import GameSession
 
 
 @pytest.fixture
@@ -12,13 +12,13 @@ def game_session():
 def test_game_session_initialization(game_session):
     assert game_session.id == "test_session"
     assert game_session.current_step == 0
-    assert game_session.machine_stats is not None
-    assert game_session.machine_stats.operational_parameters is not None
+    assert game_session.machine_state is not None
+    assert game_session.machine_state.operational_parameters is not None
 
 
 @pytest.mark.asyncio
 async def test_game_session_advance_one_turn(game_session):
-    initial_health = game_session.machine_stats.health_percentage
+    initial_health = game_session.machine_state.health_percentage
     initial_step = game_session.current_step
 
     collected_stats = await game_session.advance_one_turn()
@@ -28,18 +28,18 @@ async def test_game_session_advance_one_turn(game_session):
     assert game_session.current_step == initial_step + TIMESTEPS_PER_MOVE
 
     # Checking if health decreases after each turn
-    final_health = game_session.machine_stats.health_percentage
+    final_health = game_session.machine_state.health_percentage
     assert final_health < initial_health
 
 
 @pytest.mark.asyncio
 async def test_game_session_machine_breakdown(game_session):
-    game_session.machine_stats.health_percentage = 0
-    assert game_session.machine_stats.is_broken() is True
+    game_session.machine_state.health_percentage = 0
+    assert game_session.machine_state.is_broken() is True
 
-    game_session.machine_stats.health_percentage = -1
-    assert game_session.machine_stats.is_broken() is True
+    game_session.machine_state.health_percentage = -1
+    assert game_session.machine_state.is_broken() is True
 
-    game_session.machine_stats.health_percentage = 50
-    game_session.machine_stats.predicted_rul = 10
-    assert game_session.machine_stats.is_broken() is False
+    game_session.machine_state.health_percentage = 50
+    game_session.machine_state.predicted_rul = 10
+    assert game_session.machine_state.is_broken() is False
diff --git a/mvp/server/tests/test_operational_parameters.py b/mvp/server/tests/test_operational_parameters.py
index 7c654d2..573dddf 100644
--- a/mvp/server/tests/test_operational_parameters.py
+++ b/mvp/server/tests/test_operational_parameters.py
@@ -1,5 +1,5 @@
 from mvp.server.constants import TIMESTEPS_PER_MOVE
-from mvp.server.data_models.MachineState import OperationalParameters
+from mvp.server.core.MachineState import OperationalParameters
 
 
 def test_temperature_grows_monotonically():