I scan mine with a small infrared camera, but I do have access to a stethoscope with some medical people in the family. Whenever a hive showed no signs of a temperature, I culled it, took it home and cleaned it out immediately. My thought on early cleaning is that if I wait until spring, then I'll probably find moldy piles of dead bees and moldy frames to deal with. I'd just as soon avoid mold if at all possible. Got all mine through late Jan. last winter, then lost a number of them in Feb.- starved with frames full of honey nearby the clusters. If I was positive that they starved out, I had some honey frames to share with a surviving hive to help them through the rest of winter. Lost my first hive already this year, but it was a late season swarm I did for the animal control officer with no hopes on them making it... and they didn't. We've had a nasty (record breaking cold) October and so far, Dec. hasn't been kind at all weather-wise.