Last week the gable mounted attic ventilation fan blew its own blades off while I was at work. I was told the whole house was shaking. I guess 25-35 years of running when it gets hot caused micro-fractures that eventually lead to its demise. When I finally got to look at it the next morning the fan blades were laying below the motor as if someone had gently removed them like wings off a fly. Needless to say, I had to remove the old unit and order a new one which was only $65 including tax. The new one took a few days to arrive but I am happy to say that I was able to get it installed and it is now doing its job hopefully for many years like its predecessor and I only got shocked once while removing the old one. That's right I am one of those fools who believe in working on live electrical lines. It's perfectly safe as long as you don't let yourself become a conduit between the hot source wire and the ground.