Most things you won't use more of just because they're readily available in your home. I try to keep my freezer well-stocked with meats (ground beef, pork chops, chicken thighs, etc.) and my pantry stocked with dry goods, simply because it makes no sense not to. I picked up the habit in college in VT when I realized how easy it is to get snowed in for days (or at least the car buried and can't be bothered to dig it out!) and it was logical to have the ingredients for many days' worth of meals on hand. I keep it up now, because times have been hard lately and the paychecks don't quite reach sometimes. (Sometimes, food in the freezer is a kind of $$ in the bank, depending on your income level and situation.)
So. Are we likely to eat more pork chops in a week, a month, or a year because there are many in the freezer, than if there weren't? Maybe? But if we are, it's likely in place of something else. Maybe we grab a package of already-bought-cheaply chops instead of buying not-on-sale ground beef for that night's dinner, so that is no bad thing. Maybe, because I bought a year's worth of peanut butter, (regular-sized jars, on a deep sale, not giant jars), my kids eat more PB sandwiches than they would have. But they're not limitless eating machines; if they eat more peanut butter than they're eating less of something else. Applying this theory across the board, it shouldn't matter if you DO actually consume more of whatever you bought on discount, as long as it's something that you don't regret eating from a nutritional standpoint. Don't stock up on stuff that you consider nutritionally inferior, or don't want your family consuming on the regular.
As several other posters have pointed out, decanting large bottles into smaller ones helps alleviate the tendency to use more shampoo/ condiments/ whatever, and buying in bulk often doesn't equate to getting *larger* containers of things anyway, so much as *more* containers.
Don't try to buy treats in bulk. Snacks, (if you buy "snacks", a whole 'nother post!) If I buy 4 pints of Ben and Jerry's, it will last me... 6 nights. And then I'll feel awful. If dried raisins or cherries make you go crazy with fruit lust, do not buy a 2-pound bag. I can buy those and keep them around to make granola with, because I don't get the urge to just nom on them.