...a simple wind shirt either worn alone or over an insulating layer, makes a very real difference every time a draft finds it's way into the quilt.
not to mention how much easier it makes getting up for that middle of the night bath room break
Yep. Same idea... Keeps the air exchange in the insulating layer you're wearing to a minimum... Especially if you get up in the night. Polar fleece is exceptionally warm, and completely NOT windproof, so the slightest draft makes it cold. For that kind of thing a windproof layer is almost essential.