Lets look at the primary reasons that storage units are sold at public auctions. Some people go to jail. If they already have their property in a storage unit, it is difficult to make a payment from behind bars. If they went to jail and had a relative or friend move their property from their home into storage and the relative or friend gets behind on the payment, their property is unknowingly sold. Some people die and their family members are not aware that the deceased had property in a storage unit. Others lose their jobs or become ill and fall behind on their payments. It only takes a few months before the costs really add up and some people just can't afford to get current.
In other less tragic scenarios, a person may get a job offer and have to relocate on short notice. They pack in a hurry and everything but the essentials go into storage. Over time these items become less important and the cost to transport them to another state is overwhelming, so they just relinquish the property to the facility or quit making payments. Also, when people relocate, their addresses & phone numbers change. If there is a problem with their credit card and the facility is unable to reach the tenant, notices are placed in the newspaper and then their property is sold.