How much wear and tear occurs to a sleeping bag on a trip up Denali? Or, put another way: How many trips up Denali can you expect to get out of the same sleeping bag?
I ask because I would like to loan my almost new Western Mountaineering Puma MF (-25 rating, down, micro fiber shell) to a friend for a Denali bid. However, we're both worried about what 20+ days of continuous use will do to it. People talk about getting many seasons out of a bag, but that doesn't help me unless I know how much they used it during each season. I'd appreciate any information how many days of use I can expect out of a bag. Thanks.