How do YOU prevent over-drying?

After a few dries you'll get it, I go something similar to a previous post, when the small/bottom stems snap, I double check the bigger buds and eventually go by look & feel. If you let it dry until the larger/main stems snap it's definitely too dry. No biggie to have them slightly moist and finish them off during cure (if/when needed), much better than over-drying. Just pulled a plant this way and it was perfect, it's cured to the point of (somewhat) smokable within a week after drying, burns great, not too wet or dry.

imo the key is adjusting the fans you have to dry them around the room/conditions you're drying in to get at least 5-7 days (longer the better imo). Humidity high you can point it at them (oscillating is best imo), humidity low, bounce it off the walls/ceiling... I've never used a humidifier or dehumidifier to dry and have dried in both extremes (cool/dry and warm/humid) over the years.