Apple Watch Series 9 vs Apple Watch Series 12: should you upgrade?

If you're buying new, get the Apple Watch Series 12. The Apple Watch Series 9 is no longer sold by Apple.

Brand new, with Apple's latest chip and health sensors.

The Apple Watch Series 12 is 3 years newer, so it will get software updates for longer and holds its value better. If your Apple Watch Series 9 still works well, there's no rush, but don't buy one new.