Here is my hard and fast rule for winterizing. I winterize before I need to and keep it winterize until after I no longer need to.
In other words, there is no hard and fast rule. But if you wait to long it's too late.
If you camp in the UP, like I frequently do, if you wait until November 15 it's probably too late. If you camp in southern Ohio, you may not need to winterize until January.
Your question (I was wondering how late others folk push the season until they have to dry camp?) doesn't have an answer. Use common sense.