Re: Mistakes Happen
Several years ago I arranged for a local roofing company to replace the central heating's damaged ridge vent. I took the day off work so I would be able to let them in the house and get into the loft.
About the time they were due to arrive I decided to take a "before" photo of the old vent. However, when I went outside, I was stunned to find there already was a new vent up on the roof! I hadn't noticed it when I came home the previous evening because, being winter, it was already dark.
I phoned up the builder and they said they had come a day early and had done it all from the outside.