One of DW's passions is going to garage/estate sales on weekends to look for "antiques" and "fine china" that she thinks are undervalued. It started innocently enough---a little sculpture here, a little painting there---but gradually these things accumulated over the years, to the point that we now have hundreds of this stuff all over the house---in the garage, under the beds, in the cabinets.
I think that's fairly common. I have a neighbor whose husband did exactly that. He died ten years ago and she still has 90% of it. Her son came about two years ago and cleared out enough of the large 2-car garage to let her squeeze her little car into it, but it's still basically stuffed, along with most of the rooms in her house. It just doesn't bother her, so she hasn't done anything about it.