Time Out
I used to work on checkouts and at one point they started to care about scan speeds. The top three people on items per minute got “star points” that could be exchanged for several things including a gift card to spend in store (1 star point=£1).
I figured out pretty early that it was timed from scanning between items, not in a continuous fashion or between a transaction. If you pressed the total button it stopped the timer, so I exploited it hard. There was a target of 18 items per minute. The first month, I had 40 items a minute, and the second place was 28.
Obviously, I won the points that month. But it looked suspicious so I pulled it back a little and kept it around a low 30 to make it believable. I paid for my shopping for about six months using that trick.