Common? Ah a sort of average. In the 'real world' to expect your self defense situation to be between 5 and 12 feet is playing dice.
I'm very fortunate to have never been in a shoot out... but I have been mugged before and know lots of other people who have as well. Muggers will ALWAYS close the distance before making an actionable threat to you. "Excuse me, do you have the time?" or "Excuse me, do you have a cigarette?" "Excuse me, do you know where....?"
I have taken a few combat handgun courses (taught be LEO trainers) and all pretty much state the same thing. In a self defense situation, you will have no time to acquire a site picture. You will have no ability to physically acquire a sight picture (due to the adrenaline dump) . And lastly, if you do have the time and ability to acquire a sight picture and take the shot, you have most probably just committed murder.
Again, as far as distances are concerned.... Here's a question: How large are the rooms in your house?
I'm sure that there a billion scenarios that could be dreamed up and many of which would make a fun time training for, but they don't represent probable scenarios.
For me, in addition to cqc point shooting, I also train with sighted fire as well as longer distance point shooting. Don't get me wrong, sighted fire is a skill worth having, but in a self defense situation, to my mind, it's practical application is very limited compared to point shooting.