I've featured Derek J. Canyon here before, and he continues to deliver helpful and candid analyses of his adventures in ePublishing, on the blog of the same name.
I started my self-publishing efforts back in September 2010. Back then, I planned to commit to 5 years of writing before deciding whether or not it could become my actual career. By late 2015, I hope to have 10 novels in print. The sales of those ten novels should give me a good idea if I'm successful enough to quit my day job and become a full-time novelist.
Read the analysis here: http://derekjcanyon.blogspot.com/2012/06/how-much-do-e-authors-make-per-hourword.html