diff --git a/lib/api.js b/lib/api.js
index eb66fba..bb1e859 100644
--- a/lib/api.js
+++ b/lib/api.js
@@ -111,7 +111,7 @@ Api.prototype = {
         /**
          * If there's no OAuthKey, request one
          */
-        if (!this.requestOptions.headers.Authorization) {
+        if (!this.requestOptions.headers.Authorization || this.isExpired()) {
             return new Promise(function(resolve, reject){
                 self.authorize(function(){
                     self.method.call(self, method, function(data, response){
@@ -255,10 +255,18 @@ Api.prototype = {
             _.extend(self.requestOptions.headers, {
                 Authorization: data.token_type + ' ' + data.access_token
             });
+            // Multiplying expires_in (seconds) by 1000 since JS getTime() is expressed in ms
+            self.authorizationExpireTime = new Date().getTime() + ( data.expires_in * 1000 );
             callback(data);
         });
     },
 
+    isExpired: function() {
+        // Expressed in ms ( 10 seconds )
+        var THRESHOLD = 10000;
+        return (new Date().getTime() - THRESHOLD) > this.authorizationExpireTime;
+    },
+
     /**
      * Populates the SDK object with the services
      */