Going to be hard to judge - most mid-90's B/W games saw arcade life, so much higher risk of abuse and potential number of games making them more "used". More and more Sterns are sold new to home use, so it'll be easier probably to find nice examples down the track, and we may not see much in the way of Sterns from arcade type use. Interesting question.
Ive had my T3 about 8 years NIB
lifted the PF once to do work on it, resolder a coil
IM worked one it one pop bumper issue
CSI worked on it twice skull ramp and a opto problem
Spidey never worked on it
TSPP (gone) worked on a flipper problem once
compared to myWms bally games- the sterns are almost problem free
(keep in mind all but the csi were NIB)
so as Nick said they wern't beaten to death in a arcade