Every single time I declutter, I regret it afterward. Even if I haven't worn it for a year, I feel that I need one (for example) sequin tank top. Ever time I get rid of my sequin top because I haven't worn it, I just end up buying another. Cooking is always easier when I have the right tools. A Spartan kitchen is not as easy to cook in. And I do like to change my crafting routine without needing to make a special trip and buy everything all over again. (Except Quilting - it's just too hard and I'm not going to try it again.) Oh, and there's that weight fluctuation thing that means having jeans in three different sizes doesn't just make sense, it's necessary. Plus the books - although with my Nook, I now have all the classics that used to take a whole wall of shelves in one little book sized machine. Add all my magazine to it, and the Nook is my kind of decluttering.
So now, I don't declutter. I throw away trash and worn out clothes. I donate the odd gift and give my children items that they covet. I don't buy things I don't want, and if I do slip up, I just return the mistakes. But most importantly, I make a point of having good storage. Thanks, IKEA.