Depends a lot on the thing in question. Costco maple syrup lasts several months at least - we don’t do pancakes and waffles that often, though I use more when I use it for pork loin. Most things of chocolate, like the lyndt truffles, only last a couple weeks because I’m a chocoholic. The toilet paper probably lasts a few months. Dog food maybe one month (two dogs around 50 pounds each).

When there was five of us at home, things went a lot faster.

That is going to depend highly on what you are purchasing.

We generally will goto Costco once a week to stock up on produce and whatever we are running low on. But some items will last much longer (flour, oats, etc).

Depends on what I buy and how many people are eating it. I’ve found that the larger quantities doesn’t always mean cheaper per kg. We definitely don’t need to go there more than once a month.

I live solo and use Costco, just got to know what to buy there