It is fairly easy in this country to have too much. You can see homeless people that push a grocery cart that is over-crammed with stuff so even they can have the problem of having too much stuff. Of course, one of several problems with too much is that the oversupply might not include items that are very much needed. Don't think it is impossible to have too much and need different items at the same time.
There are events along the line of life that tend to mark changes. One of them is the children's entry into school. When your youngest begins school, the tools for toddlers such as play pens, cribs, and potty chairs can go. The tv shows about hoarding and other prompts help people resolve to get rid of the stuff stored in the basement, the attic and the back room.
Some of our neighbors organized a rummage sale and invited all the other houses in our development to sell on the same day. The sale ran for two days and one estimate of the total cash earned is $10,000 for all houses in total. We sold a Brio water table, a maze like a train set but filled with water instead of train tracks. The best we can figure, it currently sells for $200 but we took $10 for it. I quote that just to show that the retail value of the goods exchanged might be much higher than the estimate.
I think the ways things go with material divestment is funny. Say, I have an old computer monitor that is just taking up space in the basement. I would like to get rid of it. I carry it into my garage where other goods are also sitting, waiting for inspection by prospective acquirers. When I get it to the garage, the question arises: should it have price tag on it? If you had been in the basement, and said you would get rid the monitor for a couple of dollars, I might have handed you two on the spot. Now that I am in the garage, I ask myself
What is a good price?
How much will someone be willing to pay?
How much is the monitor "worth"?
How much are neighbors charging for their old monitors?
I might put a tag saying "$10" on it. Later, somebody walks into the garage and looks at it and offers me $5 for it, for this item I might have been willing a few minutes ago to pay you to haul off. But, now, I am evaluating this offer: hold out for someone else who might pay $10 or take the $5. It is a wonder that I get rid of anything.