I planted my squash earlier than usual this year. I've usually left the fruits on the vine until frost threatens, but this year it's just September, and some of the squash is clearly ripe and ready now. I really wish it weren't, because I want it to store as long as possible, but it's my fault for starting it so soon.
I suspect there is a point at which the quality of the squash will start to deteriorate if I leave it too long, but just what is that point? Anyone have any thoughts? Most discussion of picking squash is all about the problems of picking it too early.
How late is too late to pick winter squash
They should be good untill heavyfrost/freeze. Of course that increases your chances of critter damage. If they are clearly ripe, then picking and storing in a dry place will be in order. Just don't sit them directly on concrete or a similar surface and turn them every couple of weeks and they should go into long term storage fine. Some cultivars are better keepers than others, but carefull curing will get the maximum life of any cultivar.
I have all my squash in ziplock bags [of course!] for protection from varmints, which works pretty well.
They prefer to get at the new fruits, not the hard old ones.