I don't flip bikes, just buy old ones to ride or take them when abandoned (w/ potential). My basic rule in buying is to only buy vintage ones my size as the real pleasure for me is riding old bikes as well as the overhaul. The few I have sold in the last year were all to free up space/appease the household CFO. My only real goal when selling is to free up resources and provide a bike I know is road worthy / ready to carry another potential rider for many miles yet. That is the pleasure, seeing old bikes still cranking it out after some loving work.