I mostly buy used, never had a problem. Don't be afraid. Plenty of great bargains especially from those types chasing the "latest and greatest"
I bought an Opera tube SACD player MINT with box and manual etc from a very well off individual. The unit was like new with low hours ( and looks cool and sounds great) for $450 w/shipping.!! $2,200 new.
As Mr Steve McCormack told me," Newer doesn't mean better" He recently upgraded my vintage McCormack DNA1 -R/1 into a "new" SMc Audio GT22 Plus. So I have a brand new -25yr old amp that probably sounds as good as a Constellation Centaur II Stereo amp for 1/3rd of the price.
Buy used from rich people and you won't have any problems.