Having spent a few years in our IS&S department as an application analyst, I tend to spend too much time testing my apps before I release them to the market. If I make the smallest change, I load the app on multiple devices and test the change on each device. Currently, I have four devices: LG Ally, Droid 4, Droid Razr HD, and Nexus 7. If it doesn't crash on any of those, I consider the change completed and go onto the next change. Once all changes have been tested and pass, I upload the app to the market. But unlike IS&S, my Android apps are all solo. I am the developer, alpha tester, beta tester, and end user. I don't enlist any users or have external testers.
For reusability, I created a template that contains all the libraries and coding that I use in most of my apps. When I want to create a new app, I just copy the template folder with all the files in it to a new folder and rename the project. Open it up and change a few variables and the app layout and basic functions are all ready to go. This allows all my apps to have the same look and feel. If a certain function, like licensing, is not needed. I either comment it out or delete it from the new app. The template is a work in progress and I am always finding new things to add to it.
