Aside from climbing the mountain itself, the most difficult part of an Everest expedition is deciding what to take along on the trip. This is partly because Everest offers nothing to sustain life. James Ramsey Ullman, the leader of the 1963 American expedition, explains:

On Everest there is absolutely no possibility of living off the land. Food, tents, utensils, clothing, climbing gear, medicines, scientific instruments—literally everything —must first be transported for hundreds of miles across wild, inhospitable terrain and subsequently carried up the mountain itself to the high and inaccessible camps.

Taking along too many supplies, however, can be as problematic as taking too few. In addition to carrying personal items and sleeping bags on their backs, mountaineers are often expected to carry part of an expedition's communal gear. If there are too many goods, the additional weight can cause exhaustion and...