I\'m not sure whether I need to add an exit button to my app. Is there any point to doing this? And if on exiting one activity or service is not .finish() or closed properly
I agree with above post by barmaley.
Long story short, you don't need to exit your application if your concerns are related to the Android system itself. Don't worry, be happy. And that applies especially for lazy users (remember the old Symbian days).
However, if you have something in mind about your application itself, then please go ahead and do it. You can finish the activity, nullify and kill. Just be reasonable because, as always, common sense is going to be better than all the tutorials and references in the world.
Anyway, just my 2c.