I used to be of the opinion that “you can have my WM bag when you pry it from my cold, ...oh, wait, with WM, they don’t get cold.” However, I discovered Thermarest’s line of down sleeping bags and quilts about three years ago. They’re available with 650 fill down (and I’ve heard rumors they may bring out a 900-fill line in the next couple of years.) They’re only a couple of ounces heavier than the WM equivalents, and I’ve never gotten cold in them. (I do think WM ratings are probably 5-10 degrees conservative, while the Thermarest ratings are dead on.) They’re also $150-200 cheaper than equivalent WM products.

Last year, mostly as a demonstration for backpacking classes, I briefly switched to Thermarest synthetic quilt and 20-degree bag. They were inexpensive, and warm - but like all synthetics, very bulky. (I gave my down bags to my niece, who was using a worn-out Coleman Grey Fox bag from the early 90s.)

Now that the demonstration trips are over, I’m back with down. I found the down quilt on a close out sale for $175, which was way too good to pass up. I don’t intend to replace the sleeping bag, as I’ve decided (at age 68) that I’m no longer interested in going out when it’s below freezing - I’ve slept out in the 20s (and once or twice in below-zero conditions), and the t-shirt is still in good shape, so I’ll watch that weather from the comfort of home. I’m confident that I can stretch the 40-degree quilt down to the lower 30s by wearing long-johns, light fleece, and a hooded down jacket under the quilt (I’ve done it before.) So, I really don’t need a sleeping bag.

“Demonstration trip”? The groups we were leading were all new backpackers, with limited gear budgets. All of we leaders were using light to ultralight gear, carrying less than 20 pounds. I got some informal feedback from participants that they might not continue to backpack because they couldn’t afford to upgrade to the kind of gear we were using. To eliminate that perception, I bought some synthetic bags and jackets and starting carrying an Atmos pack - to show them that you could use less expensive, heavier gear and still carry between 20 and 25 pound loads, and still enjoy backpacking. It worked.