Police are taught to issue speeding tickets, break up domestic fights and measure skid marks in a accident.
In the Marines I was taught, and still do these things RELIGIOUSLY:
When you walk out of your home door, restaurant door, or any door look to the left and right. Anything out of order?
When driving stay on the inside lane at stops. In a emergency you have two ways to get away, left past traffic or if that's blocked drive over the sidewalk.
Don't let ANYONE walk too close behind you even if it's in a grocery store. If you hear footsteps that means they are CLOSE. Stop, turn to them, as you act like you are checking your phone.
Sure you have a pocket, or belt gun, but what happens if attacked in a car while wearing your seatbelt? In New Orleans the ghetto rats wait till rush hour when traffic on 10 is backed up to a stop. They walk from behind with a tire iron, break the side window, a tinted window will NOT shatter and will buy you a few moments. A ankle holster with a R9 in a Bulldog #1 is a perfect fit.
There are lots more. When my brother in law comes over, he is a Sgt on a SWAT team. we exchange training tips.