This article really has a good point. Suppose you create a houseful of waste by throwing out everything you own and replacing it with new, “green” alternatives. Even if these alternatives are recyclable, from renewable resources, etcetera, you were doing the earth plenty less harm by using your old stuff until it had done its duty.
Of course, don’t give up on buying green when you need something new, but don’t go replacing when you have perfectly good stuff. (The article linked here says it much more eloquently.)