The us govt actually sponsors some good (free) first aid training like https://www.dhs.gov/stopthebleed. That class is worth it, and i carry a basic 1st aid kit from Dark Angel medical in my backpack/car now.

I feel like I'm not very likely to need to perform CPR, but I've seen two people sustain major injuries doing yard work of all things. The 2nd time it took about 20 minutes for EMS to arrive. Had their cut been a bit deeper things could have easily ended up being much worst, and my crappy attempt at stopping their bleeding with a towel would have done nothing.

Stop the bleed is a 1 hour class, everyone should take it.