no not at all times, you have to sleep, if you are out and about, you read the street or the room and if you someone suspect get in striking distance you should be " on guard" i don't mean with your,fists up, i mean be,aware that someone might strike you, I've been doing this all my life, it's called being,street smart,
it doesn't take " training" it takes common sense, .someone MAY try and rob you, be,aware. That's a short training course,,, its like telling people it might rain, take a hat
i passed a group of youths the other day, it was dark in a deserted urban place, for fifty yards i listened for the sound of fast steps,after me, non came, i relaxed