My personal mileage with ME was that it would hum along fine, but at some point would become unstable. Once it became unstable, the best solution was to reimage it. Whatever would break did not seem to ever get better, regardless of any attempts to find or fix the issue. So the first crash, just start reimaging.

Of course, I was used to reimaging my Windows machines at the time anyway. That's something that's mostly gone away, and I think one of the better (but mostly invisible) advances in Windows.