>For my washing machine, they were unknown unknowns - I didn’t even expect there’d be a hole to drill, new hoses to buy, a cold water tap cap to remove, and a spigot PVC wall to drill out.
No, most of this was something that could have easily been known if checked after the first trip to the store but before going there again, or at minimum before the third trip. It was just so painful to read how there was absolutely zero planning and checking before execution.
While you can also do many checks and plans in software development and deployment (like calculating if the thing you want to calculate given your resources is even remotely possible, back of the envelope calculations, you know), there's still many more things that are much harder to know about and check in advance, and there's not usually a huge cost (going to the store) associated with problem solving each time.