Noticed the office staff layering plain paper and cheque paper alternately. For hundreds of cheques.
Queried why: "It's always been like that".
The printer always churned out two copies of the cheques, so you had to sacrifice a bit of plain paper to avoid printing out double-cheques.
Borough support had "looked at it dozens of times" over the years. This person had been in the same school for 20+ years, so she could tell you names, dates and what they did.
They'd reinstalled the software, reinstalled the machine, changed all the server settings, deployed print group policies, tweaked every option, and after years of callbacks given up and told the staff to put blank paper every second sheet.
It was a HP Laserjet, the ones with the old "cold blue" LCD displays. They only ever used it for cheques because it was the only printer on site that didn't jam when it printed them (cheque + sticky seal + plastic address window in one A4 sheet).
I tapped a few buttons.
Found the option that said "Copies; 2". Changed it to "Copies: 1"
Worked perfectly for years after that. I think she would have kissed me if she could. Years of "paper, cheque, paper, cheque, paper, cheque" for thousands of cheques before she printed every time...
(Yes, Borough support was in bed with RM so the system/support was basically entirely RM and HP. The same school sent back three machines five times because they "never worked". The problem? CMOS Checksum Error. I got the job there by sending a member of staff down to the watch store for 3 x CR2032 batteries. They worked fine for years after that)