As a beginner I'd inspect hives weekly. I think that is often enough that you'll catch most of what's happening in there, but not so much that you'll disturb them unnecessarily. I also do sugar rolls instead of alcohol washes, since I don't like killing bees if I don't have to. Sugar rolls are slightly less accurate, so what I do (on the recommendation of one of our other members here) is multiply the number of mites in the sugar roll by 1.3 to help compensate. I do sugar rolls usually at the beginning of the season, early summer, late summer before treatments, after treatments, and before winter.