I failed to do this last deer season. So, no practice (zeroing) and went out.
First shot, first day: 1 six point buck gut shot. Tracked him for 2 miles and lost the trail.
Second day: Had to pass a 70 yard head shot on a doe.
Fourth day, second shot: Shot at doe, aiming for front shoulder, but missed and cleanly broke both her back legs. Only reason there is any venison in my freezer is she couldn't run away very well on 2 front legs.
Moral of the story is once the gun is on, the gun is on unless you've dropped it. The shooter however is different. This year I invested in 200 rounds of bulk ammo and have been doing a little pract--ahem, zeroing this summer. With any luck the 'gun' won't be off come next deer season