If, as @smcgathyfay has found with her lasers, the tube will need replacing in 8 to 13+ years I’m pretty sure I’d be happy to call that the life of the machine.
Agreed, replacing the filter counts as maintenance, I had neglected that in my thinking. ATM, I wouldn’t really count wiping the mirrors as maintenance, depends how difficult it is.
Looks to me like you found an excellent compromise. That is a very well-rounded group and I always learn something from each show. Too bad you can’t bring Josh in, but that probably wouldn’t be fair to Josh - he’d be inundated with questions he couldn’t answer…