It might surprise you to learn that the self-storage industry has been the fastest-growing segment of the commercial real estate market for over 40 years. With one in ten U.S. households now renting at least one unit, annual revenues topped an estimated $24 billion dollars in 2013. But why, exactly, are so many Americans in need of extra storage space? Here are the five most common reasons people give for renting a locker.

1. Downsizing

Because they no longer need the space, many parents decide to downsize after their kids leave the proverbial nest. And whether they move into a smaller abode, a condo, or even into a retirement community, there is bound to be less storage space. As a result, many of them are choosing to rent storage units.

2. Inheritance

When people pass away, they often leave furniture, artwork, and other personal items that take up a lot of room. If the recipient has no place for it, he or she may decide to stow it away at a local facility.

3. Extended Travel

When people who live alone leave their residences for protracted periods of time, either for work or personal reasons, they often put their personal items in storage units. Renting these spaces is, after all, much cheaper than paying for an apartment you won’t use for many moons.

4. Moving To The City

Far more Americans are relocating to metropolitan areas than to either rural or suburban spots. Although the benefits of city living are numerous, they do not include spacious accommodations. No matter the area code, apartments in urban areas are generally much smaller and more expensive than they are in other locales. It is not surprising that urbanites rent storage units at a much higher rate than other Americans.

5. Office Space

With the cost of commercial properties on the rise, not everyone can afford to move to a larger office when their current one reaches capacity. But they can certainly afford to rent a unit or locker at a local facility and store important files, furniture, and equipment until a later date. This simple solution could save them lots of money in rent and overhead expenses.

6. No More Room

Whether good or bad, Americans are arguably the world’s most dedicated consumers. From clothes to sporting goods to household items, we buy an awful lot of stuff. Moreover, our buying habits rarely change even when we start running out of room. Most of us just keep on acquiring until our basements and attics are filled to the brim. Then, we might start stowing things in the garage or an outside shed. Increasingly, however, Americans are running out of those designated storage spaces and are renting lockers at local facilities.