Power

I always have 14 with me, 4 in the gun (3+1) and my belt pack holds 10. I'd probably take a few more as I've seen personally people who hunt with 5 or 7 that have shot an elk and not killed it due to misjudging the distance and hitting them poorly. This was my brother-in-law who always heart shot every animal I've ever seen him take, but last year he over-estimated and shot high, hitting it once then burning his 6 other shells trying to finish it.

So, don't think just because you've always only needed 1 that some day you may not want more. I think good advice would be to take as many as your gun holds plus enough for at least 1 complete reload. 2 complete reloads would be better. I know I've used up to 6 bullets to finish an elk in the past so better to have a few extra than 1 short and watch that animal get away to feed the coyotes.