It's quite easy to influence your lizard brain's urges and impulses directly through a one-time action, and much harder to manually override them through continuous conscious interference.

You can minimize the effort. I only go down isles that have what I need, so I can skip a lot of stuff without thinking about it. I avoid looking at the racks at checkout or areas that don't have what I need which again means I don't need to exercise self control.

Don't forget supermarkets stacks the stuff you don't need but may buy on impulse at the end of isles, meaning you still have to pass them.

This is where the ancient Stoics come in handy. I still struggle mightily with these kinds of things every single day, but we are animals, after all. It is certainly a lot easier for me than it was before I started studying stoicism, though.

Some gum makes the right decisions a little easier.

A list removes the need to decide at all.

I hate supermarkets so usually get in and out as quickly as I can. Often that means not getting some items on the list. I mean sure I've occasionally picked up stuff that hasn't been on the list but that's usually because it's something that should have been on the list but was forgotten about (eg milk or eggs - basics that get used frequently in a family home). However the times I walk out not buying stuff on the list far outweigh the times I've walked out with additional stuff that wasn't on the list. So I've never understood why people need such complicated systems to reduce supermarket spending like those described in this thread. But I guess everyone is different and perhaps some people like shopping and are prone to impulse buying?

I love food shopping and can easily spend an hour in my favorite food stores. Just roaming the isles, seeing what looks fresh/good/interesting that day and trying to come up with what I could use it for. I'll often head to the store to just get eggs and milk, leave with $80 of groceries and come home realizing I forgot the milk.

You're just lucky that you have an archipelago for a supermarket.

I see supermarkets as having 100 years of A/B testing to make sure that you don't stick to your list.

These include strategic floor layouts, the smell of fresh bakery goods such as bread and cakes, special offers, slow music, reduced lighting, fresh produce first, eggs in strange places, expensive products at eye level, and of course, the items in the checkout.

Having a shopping list does help. It's the sticking to it I'm curious to how easy that is.

I'm comfortable pitting my self-control against supermarkets' century of A/B testing.

Their 100 years of A/B testing has no effect on my wife.

Alternately, they have years of testing how to present things to shoppers like me, where "stick to the list" is never a hard and fast rule, but there's a conscious desire to browse a bit too.

I wonder what the overall frequencies of different customer behaviors, there, are...