Tires are probably the most important safety item on your bike. Running the last fews miles of wear isn't worth the risk. A tire with low tread depth really puts you at risk in the rain. Tread depth is what make a tire work in the rain, why take the risk with your body. If you ever crash and lay in the hospital for awhile this will become cleared to you, I know this first hand. I personally inspect my tires after each ride, it's not that much work. I use a white grease pen to mark the tire so I know for sure when I've make one round I also make sure the valve stem is in the proper location to check the air pressure the following day. Tire pressures should to be checked when the tire is cold and that will take over night. I only ride one up and have set my tire pressures to 36 & 38 and have got good wear. I've also added a tire pressure monitoring system it gives you a lot of comfort when you moving along 80+mph that all is good with the tires and that's a very good feeling.
I bet to differ. The most important safety item on your bike is the mash between your ears. You can crash for many reasons, and I am willing to guess that most crashes that do occur have little to do with the tires, but primarily with that gray mash stuff. And unfortunately, I have some experience here.
And while I agree that running a tire past the wear bars will start to impact wet traction (though not nearly as much as a car tire), here in Arizona that's not something I have to worry too much about. Depending on the brand/model of tire, I have gotten a couple thousand miles after hitting the wear bars on a rear.
Hell you should see the rear Azaro I have on right now. I hit those wear bars a couple thousand miles ago. You can't even tell where they were in a few places.
I have known plenty of Safety Natzis in my day. Much like politicians, they love to prey on people's fear. Personally, I have found common sense and logic are much more useful tools.