Really not sure, I know I just used once a week as my yardstick to avoid the urge to be taking a peek daily.
It's probably a bit much but you have to strike a balance between the advantages of not disturbing them and the advantages of using inspections to learn as a new Beek.
The other thing to consider is the length and depth of your inspection....not all inspections are created equal.
Depending on your intended goals, just because you go in a hive doesn't mean one has to pull and inspect every frame. Lots of times you can get in and out quickly and cause little to no disruption.