This and this are worth reading. Also my comment about dealing with the ammo shortage of last winter is on the main page. Man that was a dumb thing to do. Space was at a real premium in our cars for the drive but a shoe box full of .38 would have given me peace of mind. The real kicker is that I had the ammo and just didn't bring it. Oh well it was a busy time and we had lots of stuff on our minds.
In any case having a couple hundred rounds per gun is probably reasonable advice for someone who is just getting started or is cautious but not full bore paranoid. Probably enough ammo for anything other than a Mad Max scenario.