Compression sack for winter bag?

Dry down will spring back fairly well, but after a couple of -10 C/F days the bag is going to be a little damp. Compression then may damage the down.

Why compress such a lovely bag so much? Far better to treat it kindly.

Just as a more general question… Does these rules also apply to all other down bags, regardless of the rating? And also what if the bag does not get wet? Would it then be considered acceptable to use a compression sack?

> Does these rules also apply to all other down bags, regardless of the rating?
I can't see why not.

> And also what if the bag does not get wet?
There's 'wet', and there's 'damp'. Personally, I treat my sleeping bag as potentially damp after one night. I always dry it carefully when I get home. So I always avoid high compression on any trip.
Mind you, I have had good sleeping bags last me well over 10 years this way.