Adat, pulled out of active service about 15 years ago, have just recently completed digitizing my older tapes.
I have recorded less than a dozen tapes with this unit so should effectively have very little wear on the heads. I did a set/locate/stop and 1:21 came up for drum head use time, (which didn't make sense to me, I would have expected more, based on the albeit few, recordings I have done).