Trance is having a new drive chain, and new pivot bearings, however rear wheel has been off and standing now for mooonths.

bearings in the hub body are a bit on the rough side.
still spins fine, but with a definite rumble when turned by hand.
the headset is also a bit on the gravelly side (but still works fine)
none of this can be felt while riding of course!

being cartridge bearings part of me would just leave them till they are really horribly knackered, then replace them, but then again, putting new X9 and pivots all over it, kind of makes me want to do it up so the bike is "as new" (or as new it can be with forks that need a service)

how long do the STW massive leave their cartridge bearings before replacing them?

I run cartridge bearings until there is appreciable play in them.

+1 slw

If I can't feel it riding, then it's all good

these are good answers (for my wallet and my guilt equally)

Whenever I know play/roughness is there.

When I find myself wondering what that wobble/knocking is.