How often do you have to service your Studer or Otari deck ? Home not pro environment.

i had a couple of revox B77 i use in a mobile recording rack, proved so reliable that i sold spare to a very high end shop in San Diego..they use it with a protection copy Jacintha tape for demo...it sounds excellent 
ATR tape high speed big reels iec EQ
good techs abound on West Coast seattle to san diego because of the studio demand...

what are you seeking to do ?

the machine is the inexpensive bit........

Restoring Revox A77's is expensive. I sent mine to the national service center in Nashville years ago, and the restoration cost me more than the A77. It's like servicing an old BMW; there comes a time when it no longer makes economic sense.

Buying from a reputable source can also be difficult or impossible.
That's what I thought, if I use the deck for, say, thousand hours a year, I would need to have it looked over every five years or so.
But, how long do the reproduction heads last, assuming best tape and head cleaning every ten hours ? I would also treat the head with LAST tape head preservative. I do it now with Nakamichi before playing each cassette and as my tech said there was only negligible wear. The deck has thousands of hours put on it by me and I didn't buy it new, though it was used very little before.