Books: for a long time I thought that I had done something when I acquired one. Yet clearly there's a difference between the book once dipped into and on the shelf for years, and the Indian cookbook with turmeric stains all over or the tech reference with its spine worn out. I have tried lately to be more discriminating in my book buying, and not to buy another book of some type (tech, history, fiction) before I've finished the last purchased book of that type.
Books^2: When I buy a paperback novel to read on a plane (or while waiting to get on a plane :-) I often finish it in some distant city and leave it someplace where somebody else can find it. Just too much work to sell for a pittance, and too valuable to simply toss out. So I leave its fate to Fate.