I've been an appreciator of plumb-bobs since I was 12 or 13 and I can honestly say I never leave home without one. Not a day goes by where I'm looking at a doorway or other vertical structure and wonder if it's true, I simply pull out my trusty plumb-bob and string and I have to wonder no more. One of the best things is when you greet a friend and they say 'how's it hanging'.