You can check the bearings without taking the turbo off. Just take off the intake pipe on the turbo and check the play in the turbo shaft. Move it up and down as well as back and forth. There should be minimal movement.
You can also turn the shaft with you fingers and listen for any strange noises, rubbing, etc. All of which would be signs of damage. The turbo should spin freely and silently.
Answers & Comments
You can check the bearings without taking the turbo off. Just take off the intake pipe on the turbo and check the play in the turbo shaft. Move it up and down as well as back and forth. There should be minimal movement.
You can also turn the shaft with you fingers and listen for any strange noises, rubbing, etc. All of which would be signs of damage. The turbo should spin freely and silently.
Good luck!