Cornered Cat posts about the importance of the other three Rules.
I am somewhat absent-minded. Consequently, I have made the decision not to get into reloading. More importantly, it means I spend a certain amount of effort in building appropriate and redundant habits in muscle memory. For legal reasons, my firearms return from the range in an unloaded condition. Once home, the magazines are secured in their normal places, then the firearms are checked clear again, before taking them to the basement for cleaning. There is no ammo nor magazines in the basement. What there is in the basement is a 5-gallon bucket of sand, at which the muzzles are pointed, particularly when I pull the trigger as part of the disassembly process of the Glock.
The key to firearms safety is not following the Four Rules, but ensuring that you break no more than one of them at any one time. That way, any failure is merely embarrassing.