Actually, if you use high quality material and have it done correctly, that almost never happens. I've had a number of cars ten plus years old and the tint was as good as the day it was applied on all of them.
Down the road it gets all cloudy and bubbly, but if you only keep a car a couple years that's somebody else's problem. You can always have it redone, but the defrost wires on the back glass often won't survive surgery.
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.