I knew a gut with a aftermarket turbo on a 5.3. He put the turbo on when the truck had about 1000 miles on it. He had 7 psi of boost 600+ HP and when he sold the truck it had almost 70K miles on it. The only issue he ever had with it was tires and axles. The only issue most other vehicles had with it was trying to catch up. It was hammered on a daily basis I still see the truck every now and again but do not know the new owner so I don't know if it has issues now.
A engine builder told me as long as you use modest boost and keep them properly tuned they will last forever.