The sunk cost fallacy
You spend £2,000 on a super printer that does everything except make the tea. However, you soon realise that even a supposedly simple problem like sorting out a paper jam requires an engineer’s visit costing £100 per hour. It’s tempting to reason that as you’ve spent so much money on the initial outlay you should keep the printer going. But really this would be to throw good money after bad.
I encountered this situation in a school I joined as head of computing. The printer was so valuable it was kept locked in a room to which almost nobody had access, so hardly anyone printed anything. The printer really was a white elephant. I kept the printer because the previous head of computing — the person who had bought the printer — was now my line manager! However, I quietly purchased much less expensive printers for each computer room, and removed the really expensive computer from the list of available printers on the network except in special circumstances.