10 Things to Never Buy at Costco

Nothing lasts forever.

There's no argument that shopping at a warehouse store like Costco can be great for your budget. Buying in bulk often lowers your price-per-ounce, which can really add up on products you use a lot.

At the same time, not every single "deal" at Costco is really a deal. Sometimes, we're so blinded by the visions of dancing dollar signs in our head that we fail to see the reality of our purchases.

In most cases, it's a matter of longevity. Pretty much anything you can buy has a limited shelf life after which it goes bad. Even stuff that doesn't actually turn rotten can lose potency or effectiveness. It's use it, or lose it -- and its value. With that in mind, here are 10 things to think twice about before picking up on your next Costco run.

1. Spices

With the exception of salt, every spice and seasoning has a limited shelf life. This doesn't mean your jar of ground ginger will get moldy or go "off." But it will definitely lose potency over time. 

Sure, properly stored, spices can last a long time. According to McCormick, whole spices -- like black peppercorns -- can last up to four years, while ground herbs tend to start fading after about a year. 

While a year or two may be plenty of time to use up those small bottles of spices from the grocery store, Costco doesn't do dainty. And even the most prolific cook may struggle to use a pound of basil before it’s past its prime.

2. Condiments

It's easy to get caught up in buying bulk condiments because they seem to last forever. And, as long as it's sealed in your pantry, that's not far off; unopened condiments can survive for years. But as soon as you peel that protective foil back, you're looking at six months, max. Unless you run a concession stand, chances are good that gallon jug of ketchup from Costco will go bad long before you hit the bottom of the barrel.

3. Flour

If you've never thought about the expiration date on your flour, you're not alone. But flour doesn't actually last forever. Even when sealed tightly, flour attracts moisture. Moreover, less refined flours, like whole wheat, can actually contain a fair amount of fat -- and fat goes rancid after a while. 

The shelf life for white flour tends to max out around a year, and whole wheat flours can expire after just a few months. Unless you're on a holiday baking spree, you're losing money on that 25-pound bag of flour.

4. Baking powder

There are two main reasons to avoid buying baking powder at Costco: cost and time. For one thing, baking powder is pretty cheap even at the grocery store, so you're really not saving much money. For another, baking powder loses its effectiveness over time. An open container is good for a few months, at best, especially if stored in a humid environment like your fridge.

5. Oil

Oil is fat -- and fat goes rancid. Unopened oils can last a while in the pantry, but once opened, your time is limited. For example, according to Bertolli, olive oil can be stored for up to 16 months. Once opened, they recommend using it within a few months. 

A regular cook using oil a teaspoon at a time should steer clear of the vats on the Costco shelves. The one exception here may be frying oil. If you have a large-capacity deep fryer and/or fry regularly, you may actually put that gallon of canola to use before it goes bad.

6. Coffee

Coffee is one of those things that really does benefit from being as fresh as possible. Powdered coffee can go stale in a matter of days. Even if you're buying beans to grind yourself, you're looking at months -- at best -- before you've lost most of your flavor. Adding insult to injury, you're probably not actually saving as much per-ounce as you think; grocery store and Costco coffee prices aren't typically that far off.

7. Detergent

Buying dishwasher and laundry detergent at Costco may be great for your workout -- those jugs are heavy -- but it may not be as great for your budget. That's because detergents really do have a shelf life. While they won't spoil like milk, they can break down over time, losing effectiveness. A bottle of detergent past its date won't give you the same clean you'll get from a fresh bottle.

8. Personal care items

For any but the largest families, personal care items are another Costco no-no. Lotions, toothpaste, and even shampoo are all long-lasting -- but not forever lasting. Like detergents, these products all lose potency over time. This applies to effectiveness, as well as scent and flavor. If you love the way your lotion smells, stick to smaller bottles to ensure you'll always get the full effect.

9. Fresh fruit

Like coffee, produce is better the fresher it is. Unfortunately, most produce in this country travels at least a few days -- up to weeks -- before it hits the shelf. That means it's already a ticking time bomb before you even buy it. Unless your family goes through packs of produce every day, you're better off skipping the Costco produce section. (Bonus points for shopping locally at a farmer's market, instead.)

10. The last straw

Warehouse stores like Costco are prime places for FOMD -- Fear of Missing Deals. But it's important to remember that everything you buy has to go somewhere once you get it home. And storage space is finite. Every pantry, cabinet, and shelf has its limit. 

Don't buy the proverbial straw that breaks the camel's back -- or the item that overflows your storage. No matter how great a deal that must-have thing is, if you have nowhere to put it, you should probably put it back.

Think of it this way: How many things will wallow into expiredness in the back of your pantry because they're hidden behind 10 boxes of your latest bargain buy? Even if you remember it's there, saving $5 a year probably isn't worth it if you have to move 20 pounds of beans each time you want something from the back of the shelf.