That was sorta my point. The DMV can give you all the driving tests, in the world and you may pass them and keep your license.

But noone but you really knows when you are too impaired to drive....so, at some point, it has to be your decision. I didn't drive on bad days and I hope you won't either.

A unusual event, like temporarily going blind, having a heart attack, stroke...etc, cannot be guarded against and could happen to anyone.

Drive when you can do so safely and don't when you shouldn't.