Re: To pull or not to pull....
Even if there is no ice, that doesn't mean it is not cold. If it becomes really cold then water in the through-hulls could freeze even if there is no ice in the surrounding water (as it is circulating, which the water in the through-hulls isn't). Frozen thrugh-hulls is likely to create problems.
If it isn't very cold on the palce where the boat is - sure, no problem to stay in water. Many are doing that.
The advantage with having the boat in the water is the prolonged season - nearly all year! Sailing on Christmas - an experience.
To stay in water just for saving some $ - not a good argument, I think.