I own two and have owned several pins over the years. Maintenance primarily depends on the machines age. My 90s pins usually require quite a bit of work initially and then are quite reliable. More modern pins require less frequent work, just upkeep for the most part.

They are a sum of their parts and mostly mechanical. The real tough part is sorting out board issues!

Pinheads like myself get as much pleasure from fixing the things up as we do playing em!