Yarn diet or yarn allowance, this is my question !

One of the possible resolutions for the New Year is to go on a yarn diet as my stash gained a lot of weight lately.

However I don't like the idea of a diet, yarn or not, it sounds like I'm going to miss out on something, suffer for self imposed reasons. I'll try to come up with a new strategy: the yarn allowance. This sounds much better, yes, now I don't have to exercise self discipline or restraint, I can still buy yarn, no restrictions to begin with, just a budget to follow :)!
The next step is to calculate my weekly/monthly yarn allowance.

Let's see: I go SnB every week, I do a yarn shop tour every month or maybe every second month.That means I need to use my yarn allowance for all of these, including the drinks and snacks at my SnB sessions, books and magazines, and some fleece and roving for spinning.

Is 50 a week too much or too little? Will I be able to afford the luxurious fiber I am dreaming about? I don't know yet but I'll start with this amount and try to keep my yarn hunger satisfied.