I have not carried a spare in over 40+ years. I think it boils down to the advantages of not having an extra 40? pounds of dead weight and losing the extra space, and no $ investment vs your confidence you can deal with whatever pops up. After 2 million+ miles, I'm still confident, and still playing the odds.
PS, the above strategy does not apply to everyone, like daughters, wives, etc, not wanting to be chauvinistic.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
