With regard to the manometer question, as discussed, draft for a chimney can be guestimated based on where you place the weights on the baro damper. For a power vent it is essential to have a manometer to properly set the rheostat. If not, it has been my experience that you can either waste heat out the vent or create a dangerous lack of draft without knowing it.
On the door polishing activity, my problem is not only not knowing when to stop, but also seeing other doors that need polishing and bringing them home... after a while I have so many doors and such a standard of perfection I'm sure I will never get done or even start half of them!
