I've built 6 vintage bikes and I purchased every one of them without ever riding them. I immediately tear it down, inspect, measure and build a parts list. I have a specific seat height, crank length, bar height, bar width and bar reach I build to so I almost always end up sourcing different stem, bars, seatpost and cranks to get there.

I still work for a living so this gets done in my spare time, plus I like to ride a lot. Even the simplest rebuilds end up taking me 60 days to complete.