[rrwo]

Three years seems to be the standard amount of time that Google supports their phones. (A bit of web searching suggests Google may support newer phones for five years.)

I used to have a Nexus 5 phone, and when Google stopped sending updates, I rooted it and installed LineageOS on it, which gave it another couple of years life until Lineage stopped supporting the device.

[Rebelgecko]

I think it's standard for smart watches too. IIRC the first Apple Watch only got 3 years of updates. (full disclosure, I work for Google but not on Android stuff)

[smoldesu]

Aftermarket ROMs really ought to be a thing on smartwatches, too. All I want is for someone to remove the Google/Apple code and leave the watch/MP3 player functionality. If that existed, I'd probably be fine leaving my phone at home 90% of the time.