I think of all my saddle bag tools as insurance. And as don't-need-it-if-I-have-it voodoo. I'd rather carry a half a pound of multi-tool than wish I had a screwdriver, hex wrench, chain tool, etc. Same for the spare tube (though I've needed those, alas!). But sure as shootin', if I don't have a tire boot or self-stick patch, I'm going to hit another monster self-tapping bolt that will make the tire un-rideable if I don't have that boot!