Books are an easy item to borrow, with libraries existing in most towns. The due date will put greater pressure on you to actually get around to reading it, and come the due date, whether you have read it or not, good-bye to the clutter of the books. For items that you may not use again or only use rarely (such as a new tent or a kitchen appliance taking up valuable cupboard space), see whether you can borrow it off a friend. Chances are the item is just sitting in their cupboard unused, and if you afterwards you decide you do want to regularly use the item, go ahead and purchase it. Just make sure you're happy to loan any of your "clutter" to them as well.
(images: Shandos Cleaver)