Given so few high quality vintage bikes, and most of them overpriced, I typically go the "retro-roadie" route when building bikes for myself from good vintage frames (at least from the mid 70's forward). For those, I have no hope of getting my money back unless they are parted out. Given the generally losing proposition for flips unless I have high volume, I am getting selective and buying only highly desirable (to me) stuff. Typically passing on many deals I would have jumped at a few years ago.