I was just wondering if it is necessary to kill apps on my android device? Will android kill then for me? Does it use more battery? Also will cached apps drain my battery faster?
If the app has an exit/quit option under the settings, use that. If not, just back out of the app. Note, just hitting the home screen button will leave apps running. Any apps still running likely run on startup and in many cases force closing them only lasts a little while before they start up on their own again. As to the battery question, it all depends on the app. Apps left running that constantly attempt a GPS fix will run down the battery faster. Mail apps will use some battery, but much depends on how often they are set to sync.