Yes, they're definitely high maintenance. We have an old instruments only non-moving DC-10 sim in the hangars my uni is using and the guys working on that one have been struggling for the last few years to get it running. Last I heard they only had it up minutes at a time. It's running on old VAX mainframes and just to keep those running... There's always a hard-to-find piece of wiring or PCB fried somewhere from what I hear.
Flight Safety, since you seem to be in the business. Wouldn't finding replacement instruments without paying the full price be a problem too?
Cheers,
/Fred