You only need a refit when you run out of air say on a Stage III (upgrade!) or when you have a James Bond style smokescreen behind you from the seal letting go. To tear it down, refit a new bearing and balance the shaft and reinstall it would be so close cost wise as opposed to just replacing it if it shreds itself to death.

I've had lots of turbos that had a bit of play. You should only be worried and testing for play if you have the axial and radial specs on hand to worry about along with a dial indicator. A little bit of play is ok. Defining what is "little" is the real question.