I'm waiting to see how things go on my Dolnet, which from the serial number appears to be about 60 years old. It's recently been overhauled (while Jambo had it) and it plays really nicely, but I've noticed what I take to be signs of wear and tear - a little bit of play here and there, but nothing too terrible. There's a definite lack of adjustment screws all round, compared to my YAS-62, and corks and felts all over the place to keep an eye on, but I feel quite confident about taking on small jobs such as replacing a cork, or making small adjustments to ensure pads are sealing, which should help keep running costs down a bit, hopefully. Having looked at the springs, they all seem quite sturdy so I shouldn't break any if I need to do any re-tensioning.
I'm quite willing to get in there and make adjustments and do minor repairs - I haven't messed anything up as yet, and I think as long as you're careful and take it slowly and gradually, and remember where things like screws were before you move them, it's not too hazardous an undertaking.
Cheers, Bob