I have what has always seemed to me to be a very light, but very warm, airplane blanket.
I got to thinking of using it to supplement my sleeping system.
Then I weighed it. 15 ounces.
My Marmot sleeping bag, which will take me below freezing, only weighs about two pounds. Switching down to a one pound quilt and supplementing that with a 15 ounce blanket, that really doesn't get me below 40 degrees or so comfortably, suddenly seems a lot more stupid than it did.
The more I look, the more I realize that things I think I'm doing to be lighter, end up nickle and dimes ... which add up to more than I'm saving.
So the quilt/down blanket for warmer weather, the sleeping bag for when it gets colder, forget the various add-ons that are only a few ounces. By the time they all added up, it was lighter just to take the sleeping bag.