We only used to have 2-4 doorman which we got from companies, but sometimes you'd get ones who'd only just got their badge, or looked like they should be doing supermarket work. They usually went straight away unless they were really good.
I was asked from aged 18 to do the door. I felt I wasnt old enough of confident enough, almost but not quite. I was asked at a time i felt right to do door. I made a lot of friends and a few enemies. But luckily i never got hurt at all, odd scratcgh and ripped shirt etc but overall i done good.
I think i picked it up quick and learnt something new about it every time i was on the door. Never got cocky or complacent. Didnt try to look tough or mean, just smiled said hello and if something kicked off dealt with it as quickly and safely as possible.
Some guys i worked with used to disappear from front doors, then id look and it was 4 or 5 fellas who had to be knocked back...those guys just didnt wanna be the guys who knocked ppl back.