I was a trained cashier many years ago because I didn't grow up privileged so I had to work retail (and dishwasher and waiter) jobs.

Not only do I have the muscle memory, still after 30 years, I also have the added incentive of knowing the value of my own time, not being fatigued from hours of work, the ability pre-position items in the cart at an optimal orientation for handling and scanning, and foreknowledge of what items I have and a plan for how best to bag them that was made prior to my arrival at self-checkout.

So, yeah, I scan faster.

Much faster.

edit: oh man this has brought up a bunch of frustrations. Why do customers just pile shit on the counter? When I interact with a cashier, like at a gas station on a long road trip, every item I place on the counter has the barcodes oriented towards the person, so they can just "zap zap zap zap" the items rapid-fire without handling them. My bag (I live in a civilized state that has banned plastic bags) is ready and waiting, items are organized and presented in an order that make sense for ease of bagging. My payment method is ready. The experience is efficient and quick.

It takes no mental effort to do any of this and yet I am constantly stuck behind people who act as though they are purchasing things for the first time in their entire lives and the process is as foreign to them as communicating in the language of an extraterrestrial intelligence is to me.

Even a trained cashier cannot scan as fast as a trained cashier on these systems; they're slow by design. I got reasonably fast (but not cashier fast) on Safeway's and hit a wall: I kept running into false positive "unidentified item in bagging area", followed by clerk overrides. I eventually figured out that you can't place the item into the bagging area until the computer has processed it — there's a delay between the "beep" of the barcode scanner recognizing a barcode and the computer adding the item to the tab & then announcing the purchase, and you cannot hit the scale prior to that or it gets out of sync with you.

Also the only place truly training cashiers, AFAICT, is Aldi's.

The line for self-checkout is usually faster, often nonexistent. That easily eats any marginal benefit a fast cashier might offer for my 1 to 5 items.

In the U.S., particularly the Walmarts I've been to, cashiers are usually slower than the self-checkouts now.

Their self-checkouts used to be slow because the registers would verify the weight of items on the scale (the surface where you bag it) before letting you put it in the cart. If it didn't like the weight it would force you to put it back in the bag. I don't think they do this anymore. Asset protection can view a camera pointed at the scanner and bags if they think you're stealing.

Furthermore, it's hard for Walmart to retain people, so cashiers are treated like a dump stat. They won't really dedicate people to checking out anymore unless that's all they can do, e.g. elderly, so someone who's a cashier all day tends to be slow because they're accomodating that person. So you could be the fastest cashier in the world but it won't mean anything as far as raises, etc. Your fast cashiers are often pulled off and stocking unless its super busy.

I spend less time in the self-checkout queue than in the cashier queue. Overall much faster. And I don't think that's just because the shops have chosen to have more self-checkouts, it's a matter of floor space - self checkouts are much denser so they can get much more throughput.

Bold of you to assume Walmart and the like train their cashier's on speed.

(I wish I was kidding; discounters that squeeze costs everywhere including cashier throughput seem to be the exception in retail.)

In the specific case of Walmart I use the "scan and go" feature of their app, so I scan the items using my phone's camera as I take them off the shelf.

If the option is waiting in line for a cashier versus going to an open self checkout (this is almost always the case where I shop), then yes, self checkout is faster.

Even aside from the line, the only thing clerks are sometimes faster at in my experience is ringing up fresh produce where codes have to be typed in (these codes are usually on a label on the produce, but if not you have to go through a lookup procedure if you haven't memorized the code).

Trained cashier? The local Lowe's and HD have little old ladies running the checkouts. They can't even lift most of the things I am buying, and have to scan them myself.

Supermarkets usually have old slow people running them. The only time I don't use self checkout is when I have alcohol, and it is slower every single time than doing it myself.