If you are working on a side project type app my best advice would be min SDK 19 or even 21. The total # of Android users in the world makes even the minority that are on L a large userbase. You will get much further faster not having to deal with backwards compatibility. If your app is aimed at making money, the people with money are generally on the newer versions. Not everyone can get away with it (Facebook will be supporting Gingerbread forever), but don't waste your time on the old versions if you can avoid it.