Get into the habit of asking yourself a series of questions, before making a purchase: Do I really need this item? Do I already own something that can functionally replace it? How often can I imagine myself really using it, and for how long? Have I asked my friends and family if they have a spare? To be even more certain that your purchase is the right decision, you can simply just….wait! Write it down, save it to a list, make a bookmark, whatever you do, take a few days (or longer) away from the item, then come back and ask yourself the same series of questions.