I think that I carry a first-aid kit because if I suffer some accident or have an emergency I can use the kit to the hurt or injury.
a map because I need to know the ubication
stove because I need to cook to feed to me
boots are necessary to walk in the mountains
compass is necessary to don´t lost the way
sleeping bag is necessary to sleep
tent is necessary to save the things and yourself
waterproof jacket to protect the weather