Magnets

I'm familiar with the magnets demagnetizing from the entropy taking over (?), but other than that is there any way for a magnet to lose strength? I still don't get where the magnet gets the energy to move the object. For it to exert a force, doesn't something else have to lose energy? (Or mass, but I don't think magnets are performing matter->energy conversions.) What loses energy?

The concept of how an electromagnetic field exist is what I don't understand, I think.