I shoot until I start shaking and have trouble holding steady. Somtimes it's 25 shots and sometimes it's closer to 100. Lately I've been shooting in the mornings when I get home from work, after 25-30 shots I'm done and ready for bed.

As for wild arrows, just keep practicing. Depending on your setup, you might need to check the knock rotation of the arrows. If that's good, then number your arrows. If it's always the same arrows, inspect and compare them to the others, then correct the problem or stop shooting the bad ones. Also, try replacing the knocks on the bad ones. Sometimes it helps.