A thermostat should last a lifetime.
Yesterday my A/C was stuck on full blast even when I switched the thermostat to heating, so I called my HVAC technician, who told me my Nest thermostat wasn't working properly anymore (It's always sending 24V on the AC wire).
So I called Nest support to see if we could troubleshoot: I spent an hour on the phone not doing a whole lot except resetting and re-configuring it, to finally be told at the end "We don't repair them, and your device isn't under warranty" -> you should've started with that to save us both the time...
Google Nest is an expensive ecosystem that hasn't been very reliable to me (1 camera + 1thermostat have failed on me). I can't say I recommend it -moreover given the number of other Nest devices I own, I am kind of locked into it, but still seriously considering absorbing the cost of migrating to something else.
