I don't keep anything more than a ballpark, in-my-head estimate, and then only on certain guns. If I bought an older, used gun, I don't even bother, for example.
This. I have a general idea of how many rounds I have shot through my handguns, but I don't keep track of the rounds through used guns. For instance, my 1903 Springfield has probably had more rounds through it than I can count before it ever got into my hands, so I don't see any point in recording how many rounds I personally have shot through it.
Marine, NRA member, SAF Defender's Club member, and constitutionally protected keeper and bearer of firearms