More bad than good has come from day-before-match zero checks/adjustments for me. Shooting 0.2 mil right the day before the match, adjust zero, end up missing 0.2 left the next day... IF I check zero the day before, unless it's off by a lot I'm making a mental note and leaving it alone. If I'm still off in the same direction on match day, maybe I'll make a scope correction.
Then there was the one time on range/zero day when the wind was blowing 30+ mph. Left my rifle sitting on the ground with the bolt open & back while chatting for a minute. Then I jumped behind the rifle, inserted a mag, and ran the bolt fast... that is until it came to a grinding halt on the way down... Gouged the back of a bolt lug so severely that it wouldn't close on my ammo any more. Ended up running to the nearest hardware store (not close), buying some emory cloth, and sanding the high-spot from the gouge on of the back of one of my bolt lugs until I could chamber most of my rounds. That really instills confidence the day before a match...
It wasn't until I re-barreled that we found the piece of sand/gravel that blew into the action and made the gouge. It was still stuck in the lug recess.