Most trekking packing lists are written to sell gear, not to get you up the trail comfortably. This is what our own guides actually carry on a 14-day teahouse trek.
What earns a place in the pack
A down jacket rated well below what you think you need, a water bladder that doesn't freeze at altitude if you sleep with it, and — more often skipped than you'd expect — a proper set of trekking poles from day one rather than 'if my knees need it.'
Buy the down jacket rated ten degrees colder than the forecast. Everything else on this list is a nice-to-have; that one isn't.

Everything else on a typical checklist — the gadgets, the redundant layers — is optional. These three items are the ones our guides would refuse to leave Kathmandu without.
