What does it mean when you hoard things?

Each must use whatever he is or has, in as many ways, and for the benefit of as many people as possible. 

Hoarding is criminal as well as stupid. It is a sort of colossal selfishness no one can afford to indulge in. 

Let most of your keepsakes be in the hearts of other people. I repeat―do not hoard anything from furniture to ideas. 

The real things are free.