Of the gear I keep in my truck...
... the first aid kit, entrenching tool, tool box, and jumper cables have all seen use on the road at one time or another. These have been used for the benefit of others, thus far, but one of these days I might also need them for myself.
The fire extinguisher has not, yet. Neither has the survival blanket.
The tire chains almost saw use in December.
(I sometimes drive in snow/cold conditions.)
So far, guns and knives haven't been needed, which is nice, but I'd rather have and not need than need and not have.