Life span of a Turbo? Might be time for a TN...

Ok so at what point does a turbo get too old and start going out? I was pushing mine today....6% plus grade pulling 10K plus... about 3 or 4 miles. Temp in Pre-turbo hit 1300 and I backed out kept it around 1100-1200... now when I hit boost I think I get a high pitched whine... I need to make sure that it is not a Fan belt/ tranny/ power steering pump noise I will take it on a short road trip in the morning to see if it is boost or RPM noise. Still the turbo will pull 23 PSI it just sounds funny... I wonder if it is going out on me at 132xxx. I was running it in Safe tow mode but it was working it a bit to keep it up to 55 MPH. Looks like I need to take off the air filter and inlet tube and see what the end play looks like in the next day or so if the road test shows it to be a boost noise. any thing i should look for other then oil leaks and chipped Impellers?