Extreme couponers don't buy an item when they need it -- they buy it when they can get it at the lowest price. These savvy shoppers then stock up when the going's good (and cheap), so they save money in the long run. Think about it: if you run out of toilet paper, you'll be stuck paying whatever the retailer is charging to get this much-needed essential. Extreme couponers, however, plan ahead by purchasing numerous rolls when the cost is low so they avoid such expensive emergency trips to the store.
If you buy in bulk, though, you need to have space to stockpile your reserve items. The free space available in your home may determine how "extreme" of a couponer you become. Only buy what you can fit in that extra pantry, closet or garage. Otherwise, your home itself might start to look like a supermarket!