I'll pick up good stuff from other editions if it's either something I'm looking for or if it fits within a certain range of products. In general, I won't buy it if it's too setting specific; I won't buy it if I didn't buy it when it originally came out because it sucked.
I will buy it if I didn't buy it when it came out because I didn't have the chance or any money, or if I've looked at it again and decided I was having a testy day when I decided it sucked.