Nobody abuses superchargers like I do. That'* why I have a couple spares.
GM says every 100,000.
Most people here do it more often.
Once a year is probably the average.
When I change mine twice a year on the Zilla, it looks great every time. Good insurance though, with a 2" supercharger pulley.
Once a year is MORE than often enough to change it, but check it more often than that.
For the record, whe ZillaMotorsports drained Chadow427'* at over 100k, it look great too.