You've received good answers there.

My rule for this is: let's say you have a flat tire (a relatively common occurence) in the boonies somewhere, or in an industrial area on the weekend, five km walk from the nearest bus stop/phone booth/friend's house etc. Let's say that your DH does not answer his phone for a moment, or that your phone for some reason doesn't work. What do you need?

Which is why I make sure that I also have some way to patch a tire if it's slashed (energy bar wrappers work well for most of those, except sidewall holes, for which only a new tire will do, and then you're really stuck, but it's a much rarer occurence).

And the skills to change my own flats. As a woman, I find this especially empowering and important. I don't want to be at the mercy of any idiot who decides he wants to "help".....