How much IPR can be done without issues?

[plzhelp]

I had made a post prior to this but am wondering how much IPR can be done without causing any issues to the enamel. I had my front teeth done 3 times and my bottom teeth done once with a hand strip the doctor had used. I have discomfort weeks after the 3rd IPR but on the day it was done and two weeks later my teeth felt fine. I would like to do additional shaving in one tooth in the front since it shifted weird and close the small holes on the bottom teeth, but I am wondering if this is risky to do. My orthodontist said if I did not have any sensitivity that it would be okay to do some slight ipr. How many times can one do IPR using hand stripping without complications to teeth?