diff --git a/core/src/main/scala/ox/channels/SourceOps.scala b/core/src/main/scala/ox/channels/SourceOps.scala
index fd205d2b..99deffd0 100644
--- a/core/src/main/scala/ox/channels/SourceOps.scala
+++ b/core/src/main/scala/ox/channels/SourceOps.scala
@@ -793,6 +793,7 @@ trait SourceOps[+T] { outer: Source[T] =>
     *   }}}
     */
   def groupedWeighted(minWeight: Long)(costFn: T => Long)(using Ox, StageCapacity): Source[Seq[T]] =
+    require(minWeight > 0, "minWeight must be > 0")
     val c2 = StageCapacity.newChannel[Seq[T]]
     fork {
       var buffer = Vector.empty[T]
@@ -899,6 +900,8 @@ trait SourceOps[+T] { outer: Source[T] =>
     *   }}}
     */
   def groupedWeightedWithin(minWeight: Long, duration: FiniteDuration)(costFn: T => Long)(using Ox, StageCapacity): Source[Seq[T]] =
+    require(minWeight > 0, "minWeight must be > 0")
+    require(duration > 0.seconds, "duration must be > 0")
     val c2 = StageCapacity.newChannel[Seq[T]]
     val timerChannel = StageCapacity.newChannel[GroupingTimeout.type]
     fork {
@@ -976,8 +979,8 @@ trait SourceOps[+T] { outer: Source[T] =>
     *   }}}
     */
   def sliding(n: Int, step: Int = 1)(using Ox, StageCapacity): Source[Seq[T]] =
-    if n <= 0 then throw IllegalArgumentException("n must be > 0")
-    if step <= 0 then throw IllegalArgumentException("step must be > 0")
+    require(n > 0, "n must be > 0")
+    require(step > 0, "step must be > 0")
     val c = StageCapacity.newChannel[Seq[T]]
     fork {
       var buffer = Vector.empty[T]