http://en.wikipedia.org/wiki/Self_storage#Self_storage_today
At year-end 2009, a total of some 50,000 self storage facilities, owned by 30,235 companies, have been developed in the United States on industrial and commercial land parcels. There is more than 2.35 billion square feet of self storage in the U.S., or a land area equivalent to three times Manhattan Island under roof. The five large publicly traded storage operators (four REITs and U-Haul) own or operate approximately 9% of self storage facilities. More recently, in many metropolitan cities where competition among storage companies is fierce, better parcels of land near residential and commercial areas are being converted into self-storage once approved by zoning panels.
Self storage businesses lease a variety of unit sizes to residential and business customer/tenants. Popular unit sizes include 10×5 (10 feet wide by 5 feet (1.5 m) deep) which is about the size of a large walk-in closet, 10×10 (the size of a child’s bedroom), 10×20 (one-car garage), 15×20 and 20×20 (two-car garage). The storage units are typically windowless, walled with corrugated metal, and lockable by the renter. Chain-link fencing or wire mesh may function as a more secure ceiling than a suspended ceiling. Each unit is usually accessed by opening a roll-up metal door, which is usually about the same size as a one-car garage door. A controlled access facility may employ security guards, surveillance cameras, individual unit door alarms and some means of electronic gate access such as a keypad or prox card. A few facilities even use biometric thumbprint or hand scanners to ensure that access is granted only to those that rent.
In rural and suburban areas most facilities contain multiple single-story buildings with mostly drive-up units having natural ventilation, but which are not climate-controlled. These buildings are referred to as “traditional”. Climate-controlled interior units are becoming more popular in suburban areas. In urban areas many facilities have multi-story buildings using elevators or freight lifts to move the goods to the upper floors. These facilities are often climate-controlled since they have mostly, if not all, interior units. Warehouses or grocery stores are sometimes converted into self storage facilities. Loading docks are sometimes provided on the ground floor. Also, complimentary rolling carts or moving dollies are sometimes provided to help the customers carry items to their units. Urban self storage facilities might contain only a few floors in a much larger building; there are successful self storage businesses cohabitating with light manufacturing, office tenants and even a public school.[citation needed]
According to the “Self Storage Demand Study – 2007” (published by the SSA) one in ten U.S. households now rent a self storage unit. The growing demand for self storage in the U.S. is created by people moving (some 40 million Americans move each year according to U.S. Census data), and by various lifestyle transitions, such as marriage, divorce, retirement, a death in the family, etc.
Customers are generally allowed to store any non-hazardous, non-toxic, non-perishable material in the facility: personal items, furniture, motorcycles, overstocked retail wares, etc. Customers are prohibited from sleeping or otherwise living in the room. If the customer fails to pay the rent, a lien is placed on the customer’s goods and they are sold at auction based on the provisions of that state’s lien law. The storage facility lien rights are codified in most states. The customer is still responsible for any rent and fees due if the auction does not clear their balance. (i.e. California Self-Service Storage Facility Act, Business & Professions code Sec 21700 et seq
The national Self Storage Association (SSA) was founded in 1975. The SSA represents some 6,000 companies in the United States that own, operate or manage some 22,000 facilities.