8 + 1 in the gun ( in a 1911 ) is all I ever carry....
The scenarios on mobs, multiple attackers, etc....are over-rated in my view. Even if you have 3 or 4 attackers...if you kill the one closest to you first, chances are pretty high, the others will run - even if they are armed. Besides, that still leaves me 7 rds ( after I kill the head mutt )...
If I wanted to carry a gun like a Sig 226 ( and a standard mag held 12 or 15 - depends on caliber - then I'd carry it will a full mag plus 1 )....