Nuts have a high oil content and will go rancid in just a few months.

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Specific Items You Shouldn't Buy In Bulk

These bulk items might seem like good investments at the time, but won't add up to as much long-term value as you would think.

  • Nuts: You might think that nuts could sit in the pantry for months and even years at a time without going bad. But nuts are actually very high in oil. And although those oils make nuts a healthy source of unsaturated fats, they also mean that nuts will go rancid within four months (six months if they are in their shells) [source: Shelf Life Advice].
  • Brown rice: Like nuts, brown rice has high oil content because, unlike white rice, brown rice still has the germ attached. That's what makes it brown and generally healthier than its white counterpart, but also more perishable. Don't buy more brown rice than you can use in about six months [source: Shelf Life Advice].
  • Cooking oil: If nuts and brown rice spoil quickly because of their high oil content, you can bet that pure oil will go bad quickly for the same reason. Cooking oil goes bad within one to three months of being opened [source: Shelf Life Advice]. So, gallon jugs of oil may be a good investment if you plan to do a lot of deep frying, but otherwise, stay away.
  • Spices: Little jars of spices can be expensive, while large tubs can be dirt cheap by comparison. But those bulk spices are really only worth buying for restaurants or food service professionals. Because spices lose their flavor over time, you'll have to refresh them in about six months [source: Fiegerman].
  • Bleach: Bleach loses potency in only about six months, so most households probably won't use more than the typical gallon before its cleaning power is gone [source: Lieberman].
  • Bread: Unless you have a huge family, or you're carbo loading for a big marathon, you're making more of an investment in mold than in cheap lunches.
  • Candy: Even if you find deals on candy and other snack foods in bulk, having so many on hand can increase the temptation to overeat.

Read on for more information and tips on how to improve your shopping habits.