Elizabeth S. Craig is my kind of hero in the writing world, she was successful through one of the Big 5 publishers but she eventually went her own way. Her blog is a gold mine of resources from other writers and her own articles.
In this post, she explains her reasons for going with self-publishing. Things like releasing when you want, price control and making more money are excellent reasons.
But my favourite reason is how her idea of validation changed:
“Originally, it did feel good to be validated by a gatekeeper…I was a newer writer and I needed that. Now, I prefer reader validation. It’s ultimately more valuable.”