When does building a stash slip over to becoming an addiction?

I couldn't resist the $1.80 per ball price on the 100% Pure Australian Wool when I was in Spotlight the other day. I know it is processed in China, and ideally I would like to buy wool that was grown and spun in Australia, but it was hard to resist. Especially as it seems they have gone back to the tighter twist which is much nicer to work with.

So when is enough, enough?