12 things I would never buy at Costco (even as a die-hard shopper)

Mayo (and other massively-sized products)

I have a hard time understanding who could ever need this much mayonnaise in their life. Unless you are buying for a large, sandwich-loving family or an event, this is a huge amount to consume.

At $13.99 for 1.8 L, this is a good price. And if you'll use it, great. But be realistic with yourself and consider whether you first have the fridge space for it and, second, will use it up in a reasonable timeframe. If not, shop elsewhere.

• Costco shopping rule: Only buy food in quantities that match your lifestyle. It's not a deal if you don't use it up.
• Other culprits: All condiments and spreads (e.g., ketchup, jam, honey) at Costco are widly oversized.
  

Tomato sauce (and other pantry staples)

Costco has an awesome selection of pantry staples like this organic tomato sauce. It's a good deal at $18.49 for 12 large cans, but the truth is that tomato sauce is a cheap product in almost any store. Even Dollarama has cans of tomato sauce for less than $2.00 a pop.

So if you really like this Kirkland brand or eat pasta nearly every day, have at it. But know that this type of product is cheap in almost any store you'll go to, so you can find a low price on the quantity of cans you'll actually use.

• Costco shopping rule: Don't get pulled in by cheap prices on staples that are always cheap.
• Other culprits: All your canned goods like tuna, pasta sauce, or canned vegetables — plus dry products like pasta — are typically very cost-effective no matter where you go. You don't really benefit from Costco economies of scale here.
  

Duplicate products

If you haven't kept up with water bottle trends, you should know that these Owalas are having a moment. And, look! Two of them for $39.99 at Costco!

It's a good deal, but that's where they get you. Do you need two, or do you only need one? Because unless you're giving one away to a friend, you don't need that second one, and it's unnecessary spending.

• Costco shopping rule: Avoid duplicate products unless you reasonably need more than one.

Family packs

In the same vein, Costco sells a lot of products in family packs. These toothbrushes may only be $16.99, but because of how infrequently I need a new toothbrush, it makes no sense to buy. The most likely scenario is that I'll forget I have them and keep buying more.

• Costco shopping rule: Avoid family packs of infrequently-used items if you're shopping for one.

OMG clusters (and other things I'll devour)

I am kidding, of course. These are one of the best products at Costco and worth a spot in my shopping cart.

But we all know how easy it is to grab all the new and delicious snacks at Costco, only to come out of the store having spent $300 on some less-than-healthy options.

• Costco shopping rule: Wisely indulge at Costco and definitely don't go shopping on an empty stomach!

Oil (and other things that go rancid)

All of your oils and other high-fat-content products like nuts can all go rancid if not consumed in a reasonable amount of time. This can not only taste bad, but be bad for you. And even if you're getting a good price on it ($18.49 for 2L of olive oil), it's not worth it if it ends up in the trash with a funky smell.

• Costco shopping rule: Limit your quantities of food items that can go rancid in your cupboard.

Bagels (and other things that are not worth the hype)

I've spent a good deal of time trying and testing Costco bakery products, so I know what's worth the hype and what's not. And I have to say, without being too dramatic, that these Costco bagels were the biggest let down I've ever faced by a carbohydrate. They were just not good.

And so I won't buy them again, easy enough. But I do find that there are so many products at Costco that are so cheap and such a good deal, that I have to remember that if I do not like it, it's simply not worth it.

• Costco shopping rule: Buy what you like, not only what's cheap or what other people like.

Trendy products

Costco is definitely in the know with the wellness trends that circulate online. Collagen is one of those things I've heard a lot about, with its supposed benefits. I'm honestly kind of curious to try it. But since it only comes in a HUGE size at Costco, I won't buy it there first.

Better to get a new product in a smaller quantity, see if you like and use it, and then go for the bulk option to save money.

• Costco shopping rule: Don't buy new or trendy products in bulk before you know you like it.
• Other culprits: Most self-care items, like lotions, makeup, supplements, etc., are sold in bulk at Costco. If you love the product, go for it. If you're just checking it out, maybe start smaller.
  

Produce (and other things that rot in my fridge)

I aspire to be someone who eats this much salad, but I'm just not. I have had boxes of spinach and lettuce go bad in my fridge too many times. Now I know: Costco-sized produce is too big, and it's going to rot in my fridge.

• Costco shopping rule: Be realistic about how much produce you'll eat, and buy based on that. Eliminate food waste by eliminating veggies from your diet. (Kidding!)

Home fixtures

I know a lot of people swear by Costco's home fixtures like lighting, faucets, doorknobs, etc., but I'm not sold. It's not that these aren't good options, but there are limited options.

Unlike going to Home Depot, Canadian Tire (or your store of choice), there are only a couple of choices of each item. You might not like those particular ones, or you might want something less generic than what everyone else with a Costco membership has. And Costco employees are not trained to know as much about these products as those at a specialty store. So, you might not get your questions answered.

• Costco shopping rule: Know when you need a specialty store. Just because Costco sells everything doesn't mean you need to buy it there.

Sushi

Costco has a lot of great premade meal options. A lot. And I'm not even saying that their sushi is bad. What I am saying is that there is guaranteed much better sushi down the road at your local sushi joint. I think some things are worth getting made fresh and with love.

• Costco shopping rule: Some things are just better elsewhere.

Oversized freezer products

If you have enough freezer space for this gigantic box of Eggos, then I'm happy for you. I do not. So even if I thought I could eat this many, I cannot fit it in the space I have.

• Costco shopping rule: Think about your physical storage space before buying in bulk.
• Other culprits: Pantry items like multi-pack cereal boxes or even the well-loved Kirkland paper towels and toilet paper... I just don't have the space.