It's true, energy does "wear out", it;s just not lost. Think of it like this - you send a heat pulse down a wire to a friend in alaska. As this pulse moves along the wire it heats up and causes the wire to glow. This means that energy is lost to heat and light energy, so, if the source of heat was weak or the distance great, by the time the heat reached your Alaskan friend, the wire is cold and no heat is felt.<br />This, coincidentally, is why electricity, when transmitted over electric wires, is "jumped up" and then "stepped down". If it wasnt, it would "wear out" before it got to your home.<br />Energy can not be destroyed, however, this is a fundemental rule of physics. It, as said above, simply changes type.