When enough is enough?

How do you know when enough yarn is enough?

I promised about a month ago that I won´t buy new wool (unless there is a great reason for this, like custom rush project or something) before I have used some of my old stash.
Now, weeks later, I have about 2-3kg more yarn in the house, and I struggle with finding a place where to storage it.

But I´m sure that all knitters know the feeling of going to local yarn store for "just" seeing what´s new, and ending up with bags filled with stuff. I think I have NEVER left a yarn store with empty hands, except once in Slovenia when they had only acrylics in stock.

Sadly I don´t have much time to knit these days, because I need to spend my time between university and some work projects. On Monday I´m flying to Brussels for a week, to do some European Media work, and I don´t think I will take a risk to bring some needles with me, because I have never passed a security check in the airports with my needles, no matter if they´re metallic or wooden.