Reading the natural mite drop on the tray after autumn treatment — what daily number sends you back in before winter?

Tyrol, 18 years, 24 colonies at two altitudes. My autumn treatment finished three weeks ago and I now have clean trays under all of them for a seven-day count. I trust the drop more than I trust my own memory of a wash done in a hurry. What I'm after is other people's action thresholds this late. I use natural drop as a screening tool: single figures across a week and I leave them alone until the broodless treatment; a colony throwing dozens of mites a day in late October gets looked at properly, because at this point every mite is riding on a bee that is supposed to live until March. Two caveats I'd add for anyone new to trays: a screened floor with no tray for months gives you nothing, and ants or beetles will clear a tray overnight, so smear the edges or check daily. Also, wax flakes and chewed cappings tell you where the cluster is sitting, which is a free bonus. Curious what numbers other people act on, and whether anyone finds the drop useless once the weather turns cold and flight stops.