That is my experience as well, second or third time I'm vastly improved (not as good or as fast as a pro still, but upgraded to 'acceptable') since I've learned from the largest mistakes. Too bad I have to live with those mistakes though since I did them to my house!
To me it's like painting. Yes, I can paint my walls. But hiring it out is substantially faster and you get people who do nothing but paint all day every day to knock it out.
