I checked one of my hives yesterday for mites. Used a sticky board. Left it in 24 hours, I counted 25-30 mites.
Should I treat them? I use "Mite-Away Quick Strip". I don't want to treat unless it is necessary.
Do the same thing twice more to get a 3 day count. Divide the total by 3 to get an average. If the hive has 1 brood box, treat if the average is more than 20. If it has a double brood box, treat if the count is above 40.