Compulsive hoarding, also known as hoarding disorder, is a pattern of behavior that is characterized by excessive acquisition and an inability or unwillingness to discard large quantities of objects that cover the living areas of the home and cause significant distress or impairment.
Hoarding is the persistent difficulty discarding or parting with possessions, regardless of their actual value. The behavior usually has deleterious effects—emotional, physical, social, financial, and even legal—for a hoarder and family members.

For those who hoard, the quantity of their collected items sets them apart from other people. Commonly hoarded items may be newspapers, magazines, paper and plastic bags, cardboard boxes, photographs, household supplies, food, and clothing.