If you could see some of the guns that come into my shop that have been dropped, fell out of treestands, been in the vehicle during car wrecks, etc.; you wouldn't hunt five minutes from home without a backup. Even lacking any obvious damage to a rifle, I have seen times where a hunter missed several high percentage shots - didn't really know where the bullet was hitting - and no real opportunity to check zero in the field. Gun changed POI for some reason unknown at the time. Just grab the backup rifle and go.