You should be able to check this from the Operating Menu.
We don't actually have a DSR-11 here, but we use a DSR-20P, I imagine the menu is broadly similar. There should be a menu setting called HOURS METER (it's actually not really a setting because you can't change it). Select that and you will get a figure for DRUM ROTATION, which is total hours of drum rotation with tape threaded in increments of 10 hours. Also THREADING, which is not an hours meter at all, I think it just counts the number of times it's been turned on. Either that or the number of times it's been asked to do a tape operation (the manual's not very clear on that).
Not as useful as the high-end gear, which will give times for record and play, as well as operation hours.
It's difficult to say what is 'high' usage. Anything in the thousands certainly. It also depends how the machine has been treated. Our DSR-20 has done about 300 hours in the last year and a half. We haven't had any problems with it so far, but we treat it well and don't mix tape stock if at all possible. (Switching tape stock repeatedly can cause head clogging problems, so it's best to pick one brand and stick to it.)
Hope that helps
