I hang on to books etc for a long while, then every so often have a huge purge and get rid of loads. It's not out of a need to get rid of clutter, I have the space. It's almost like a mental cleansing.
It's arguably a poor strategy in the long run, because sometimes I'll take some clothes to the charity shop and end up wishing I'd kept them when they come back around (and sometimes re-buying similar).
It really is a kind of mental struggle for me, which I can't express well. I obsess over having the exact right combination of clothes / cookbooks / flatware / shoes that works for all possible scenarios, but not having a single extraneous item. I've been like this for as long as I can remember.
The clothes I do have though, I think, are interesting and stylish.