The Wisdom of the Ages - Age 7 In This Case

My oldest, Kelby, is really getting into the act!  At 7 years old, he is fully aware of what a depletable is and quickly educates others should the subject come up.  Yesterday, we were doing a little cleaning and I gave him a Magic Eraser cleaning pad to 'erase' some errant crayon marks that a certain 2-year-old happened to leave behind.  Kelby marched right up to me and informed me that I could purchase more of these cleaning pads since they disintegrate as they are used; therefore, they are most certainly depletable.  Later, while playing in the snow with some neighborhood boys, however, he began to fuss about his little sled because it was not working well for him.  I overheard him telling the boys that he could not buy a new one, though, because sleds are not depletable. Not sure what their response was but I imagine it involved raising their eyebrows and uttering, "Huh?"