Even if you are not planning on developing unique icons inside of your application, you are definitely going to need a unique app launcher icon. Incorporating a unique icon into your application requires several different version of each piece of art such that the icons show up in the appropriate resolution regardless of the screen size. I say “several” because I don’t know off the top of my head exactly how many it takes. And I don’t know that off the top of my head because I use Android Asset Studio to do the legwork for me. This is a simple, free no-brainer, so there is no point in writing more about it.
Getting Started With Android 