You're apparently confused. Used items aren't "exempted", they're simply not subject to being taxed a second (or more) time -- "used" is, in and of itself, an imperfect shorthand for "previously taxed".
WRT 13, how about previously taxed income that was saved or invested intended to be spent later with no tax penalty. What is your solution? Should we get a pre-index payment on $trillions in accounts. Wouldn't that be "fair" like a prebate?