At 57,000 miles no real problems. Depends on condition. Well taken care of? stored outside? (I wouldn't touch it!)Always garage store? (That's good!) Ever dropped? Was the bike ever Hydrolocked? Look it up!
Carbs could be due for a good cleaning. Valve adjust. Maybe front wheel bearings. Are you doing the maintainence youself? Dealer maintainence equal---$$$ !
If this bike was taken care I wouldn't have a problem buying it with only 57,000 miles