My take on it is to make a decision before you do anything to the bike whether you're going to keep it or flip it. Sometimes it takes a little time to decide, but the route I take is different fixing a bike for myself vs. fixing it to sell. I've got no regrets at all, except I kind of wish I kept a Schwinn World to use as a winter beater bike, but a beater bike in my size should be very easy for me to find next summer if I have the mind to do so.