[jacquesm]

For sensors I can see how you could do that (piezo with a small weight attached) and it will likely live a very long time. But for an MEMS actuator that would be driven to oscillate it would be a lot harder to make that long-lived.

[Zigurd]

To the extent I can find serivce life specs for MEMS tuning fork gyroscopes, which are driven to oscillate, they say "more than 100,000 hours" - about 10 years of powered-on time, which, for an automotive application like roll-over sensing, is essentially forever, since cars have a low duty cycle.