The pressure plate and drive hub plate would likely be too thin after a while . My guess would be after 5-10 grinds it would be cost effective too just buy new .
Now how many floaters you could change in the same time frame .
Maybe three times so 15 - 30 refreshes with a grind every now and then .
It really depends on how the clutch is set-up, treated, and maintained. If it hasn't gotten hot and warped the backing plate, you're good to go a very long time. The pressure plate and backing plate gets reground on every rebuild in our shop. If we have to take off .010" each time, that's a ton to have to shim with thicker floater discs, etc. The thinner the backing plate gets, the quicker it warps with heat abuse again.
I've seen clutches come through our shop that are 20 years old and still be good candidates for rebuilds. I've also seen others that were pretty much junked after just one race day (seriously.)