The (new) 10 Essentials
The Mountaineers Ten Essentials has been used since the 1930s but was formalized in 1974 when the iconic list debuted in the third edition of “Mountaineering: The Freedom of the Hills.” The list was later revised to be more categorical, and your 10 essentials kit may have more than 10 items in it. I like to keep a 10 essentials kit pre-packed in a stuff sack, so I can easily transfer it from bag to bag without missing anything. If I use anything or is broken, I am sure to replace it immediately upon returning home (you can even set an alarm so you don’t forget!)
THE TEN ESSENTIALS
Navigation: map, altimeter, compass, [GPS device], [PLB, satellite communicator, or satellite phone], [extra batteries or battery pack]
Headlamp: plus extra batteries
Sun protection: sunglasses, sun-protective clothes, and sunscreen
First aid: including foot care and insect repellent (if required)
Knife: plus repair kit
Fire: matches, lighter and tinder, or stove as appropriate
Shelter: carried at all times (can be a lightweight emergency bivy)
Extra food: beyond minimum expectation
Extra water: beyond minimum expectation, or the means to purify
Extra clothes: sufficient to survive an emergency overnight
Items within brackets [ ] can be shared by a group.