the majority of apps that i use exit cleanly when i use the Back button to quit the app, i.e. they leave no running services. some system apps continue to run forever, like google maps, but that is understandable as they are system apps. but i have found two apps that leave running services even after you quit that are NOT system apps: camera360 and mantano reader. they are not/should not be doing any processing in the background, yet the processes remain. i contacted the 2 developers about this, and one of them claimed this is normal android behaviour, and its supposed to continue running even after quitting, and you have to force-stop it if you want it to truly quit. this seems strange to me. what are the actual android guidelines here? is it ok to leave things running when the user has specifically chosen to quit by pressing the Back button rather than the Home button?