Butter might be one of the best examples since it's one of the best things to buy in bulk to save on costs, and folks who cook use an epic amount of it.
I used very little butter living alone and not cooking more than an average American, if not substantially less. I then got married and now have a family where we are cooking at minimum one meal per night, including some baking.
I'd be surprised if we didn't go through 4lbs of butter per week on average at this point. We typically sub butter in for most oils, as those oils were subbed into recipes during the anti-fat crusades a few decades ago. When you do this your consumption increases even further.
If you tend to not cook yourself or avoid animal fats like the majority of people I could see butter usage not being that high.
Butter also freezes indefinitely, so having less than 90 day supply on hand (12lbs or so) just seems irresponsible to both my family and society as a whole. Keeping even just 30 day stores of staple products seems to be a thing of the past in the US, but I feel it's setting us up for tears.
Edit: Others have already said it, but Costco is actually fairly bad in general for commodity items like butter or rice where you don't care about brand. You will likely find far better deals on "generic butter" at your local restaurant supply store, or even just regular sales at your local supermarket. Ethnic stores for things like bulk rice will almost always be substantially cheaper as well. Costco is rarely the cheapest unit cost, but it wins on convenience.
Where Costco shines are the few specialty items they run through way more volume than most such as imported Kerrygold butter and that sort of "upscale" branded items. Their white label booze is also substantially cheaper for better than average quality as well.
>If you tend to not cook yourself or avoid animal fats like the majority of people I could see butter usage not being that high.
Yeah, I guess that's the rub for me. I will generally use olive/vegetable oil whenever possible and I don't cook to the extent where I have a bunch of unavoidable butter recipe's to begin with. I keep a small bin as a general "just in case" measure but I sometimes don't even go through that.
Also only have a small freezer, so the thought of freezing butter simply never occured to me.
What? Butter is one of the main things I get from Costco. It actually is cheaper than my normal grocery store in that case (I agree with the earlier post in the thread that Costco isn’t always the cheapest.)
I love butter. Especially the Irish butter that just tastes so much better than "normal" butter. Either butter is significantly cheaper at Costco than our grocery stores. I buy like 10lbs and it lasts a few months of cooking etc.
There are definitely some items I don't buy at costco simply because I don't need that volume of food.