The issue for many apartment-dwellers is storage. You can't store a year's worth of detergent, toilet paper, and cleaning supplies in an apartment.

Costco really incentivizes shopping in bulk, from the huge value-pack sized portions to the focus on frozen & dry goods to the super-sized carts to the anxiety-inducing shopping experience. My wife and I shoot to go no more than once a quarter, just because it's a hassle.

We found our habits (and need for Costco) changed dramatically once we moved into a home and could now put in a chest freezer and pile toilet paper rolls in a corner.