Well, I do subscribe to the Brady Bunch theory on this. You know what I mean, one gun per month.
Unfortunately, my finances quite often stop me from doing my share. In reality, I buy a new weapon when I can afford it, find one I am interested in, and have no higher priorities for the money. And all three of those must happen at the same time. There are lots of times I have found guns I am interested in and could not afford it, and a few less times I found one I was interested in, but could not convince myself it was the right time to buy that particular gun (usually other things to do with the money). I am just guessing it has worked out to about once every six to eight months for the past four or five years.