2) When fitting a temporary handle before fitting the mortice, consider the position of the receiving doodad on the wall, before you drill.
3) when commissioning new windows, never ever buy, as the only opening window in a room, a window which is smaller than you can comfortably climb through.
4) before climbing through the uncomfortably-tiny window after making above mistake when fitting door, pause carefully and consider the location of all the tools and gadgets you will require to remedy the situation. Otherwise, repeated journeys may be required.
5) all the above go double if you are the only human being in the house.
Oh well, we now have a new door and doorknob.