For the everyday at work carry spare mags (dress is business):
1911's: 2 10rd, 1 8rd
XD: 1 13rd
For the I am going into possibly shady area's:
1911's: 2 10rd, 3 8rd
XD: 6 13 rd
and yes it all fits on the belt just nicely and conceals nicely under a dress shirt.
and this is not counting the days that I carry my backup, seems to be less and less these days with the changeover to more ammo for the primary.