So as part of professional development, I assume everybody uses some form of source code control and revision tracking.  This allows multiple developers to work together, and also a way of tracking changes.  Sometimes they're also used as a way of 'branching' off new features and then integrating them back in once the feature is stable enough.

My question is more for the hobbyist who works alone.  Generally there's no need for many of these features.  So do most hobbyists use some sort of source code system for their own projects?  If yes, why?

For myself I do it just as a way to track changes.  I never need to branch anything.  There's nobody else that I share stuff with.  I suppose I also use it in a limited way to track bugs.

So, do you use a source code control system?  Which one? Why?

Thanks for taking the time to answer.
--Grant