I grew up thinking that all these New York folks carrying a single bag of groceries down the street had the right idea: every day, fresh and new, doncha know. This was, of course, long before I had to start shopping for myself, and I learned the wisdom of going as little as possible:
[S]hop with a list and go once a week for your main trip. Go more than once a week only if you have to restock on a necessity (such as milk in our family), or if you’ve run out of a critical item (cat food!). You may be able to cut your grocery trips to every other week if you have a large refrigerator and pantry. This does mean that you don’t take advantage of each week’s loss leaders but that may not matter as much as avoiding the store altogether and spending even less.
If you are forced to make that emergency trip, then make yourself buy ONLY the item you need. Walk into the store and do NOT use a buggy, which would encourage you to fill that empty space with impulse buys. Don’t even take one of those carry baskets. Carry baskets, small carts, and large buggies: each one lets you put more stuff into it so you buy more stuff. If you hand-carry what you need, you’ll buy less.
It’s a rare month when I show up at the supermarket as many as six times. Most often, it’s a Saturday trip for regular restocking, and a trip to Braum’s about every third Wednesday to silence that damnable craving for Rocky Road. Then again, the only one eating around here is yours truly, so I always know what I need to buy and what I’m already out of.