Nikwax Down Wash
That said, the bag may be near the end of its natural life, or in need of some TLC. If you really like the bag, its certainly worth trying to save it by taking it to a laundromat and washing it with a down-specific cleaner such as Nikwax Down Wash ($9; www.rei.com). Dry it thoroughly in a dryer, tossing in a few tennis balls to knock the down clumps around and break them up. Then give the bag a good shake and lay it out. If it was rated to minus 20 when new, it should have at least six inches of loft. You also should be able to hold it up to a bright window or light without seeing voids in the down.
If the bag is flattish and voids appear, then the bag is kaput. Thats the way it goes25 years is a good, long life for any piece of outdoor gear. New bags rated to minus 20 arent cheap, but if you think of it as a long-term investment, theyre not so bad. Western Mountaineerings Puma Super Microfiber is a minus-15 bag that has lots of durable 850-fill down and a high-performance polyester shell. Its $510 for a regular-size bag (www.westernmountaineering.com). EMS also still makes bags, of course, including the Mountain Light -20, which uses 725-fill down and costs a bargain $299 (www.ems.com). It weighs four pounds, versus the three pounds, four ounces for the Puma, but thats not too bad.
For a comprehensive selection of sleeping bags, visit Outside Onlines Sleeping Bags Buying Guide.