I carry 3 levers.

This is something you should practice BEFORE you need to use it - like at home, and there are some good youtube videos on changing a tube in a tire, moujnting, disnounting, etc. There are a lot of "tricks" to easily (as opposed to near impossible) removing and mounting a tire - especially in regards to not damaging and correctly seating the tube, and finding the cause of the falt - which is essential or it will flat again. Also, even if you only go 5 miles from home on your mtn bike, carry a kit unless you like walking 5 miles.