A pack rat in today's vernacular is known as a hoarder and associated with mental illness. The visual is usually of an older woman with things that need to be discarded and left in their home sometimes accompanied by the cat woman who has cats roaming around. It's a pretty disgusting to me.

There are many reason people hold onto things that can be defined by their personalities, often reflected in their astrology and numerology charts. Reasons can include sentimentality, attachment issues, fear they might need the item one day, separation anxiety, OCD, other.

Many people people save items because they think somewhere down the line they will need them. In today's world with technology one just has to save something to computer and perhaps a back up drive. But then there will the sentimental things like clothing not worn for years, or other things that if the person who owns them Hass to find them may take a long time to do. It's all part of the craziness of reality.

The term Endowment Effect refers to people's tendency to place an extra value on things they already own. It is also known as divestiture aversion and is a hypothesis that people value a good or service more once their property right to it has been established. In other words, people place a higher value on objects they own than objects that they do not. In one experiment, people demanded a higher price for a coffee mug that had been given to them but put a lower price on one they did not yet own. The endowment effect was described as inconsistent with standard economic theory which asserts that a person's willingness to pay (WTP) for a good should be equal to their willingness to accept (WTA) compensation to be deprived of the good. This hypothesis underlies consumer theory and indifference curves. The effect was first theorized by Richard Thaler. It is a specific form, linked to ownership, of status quo bias. Although it differs from loss aversion, a prospect theory concept, those two biases reinforce each other in cases when the asset price has fallen compared to the owner's buying price. This bias has also a few similarities with commitment and attachment.