BY TRAVIS MORROW AND BRAD HADFIELD

e’ve been thinking about self-storage all wrong. The industry has long been aware of the four Ds that draw people to a unit: death, divorce, downsizing, and displacement. But there’s a first D that sets them all in motion, and once you recognize it, you may never look at your business, or tenant behavior, the same way again.

Every self-storage operator has seen it. The tenant who spends hundreds of dollars each year storing belongings worth only a fraction of that amount. It’s the furniture not sat upon for years, collectibles untouched for decades, or boxes never even opened. On paper, it makes no financial sense: The storage bill ultimately exceeds the value of what’s inside the unit.

This paradox has always been explained by way of the four Ds. These life events create an immediate need for space, and they continue to drive millions of rentals every year. But there’s a lingering question: Why keep the stuff? Why not sell, donate, or throw out unnecessary items?

Before death, divorce, downsizing, or dislocation ever send someone to a storage unit, a more basic human tendency decides whether they keep their belongings in the first place. It is disposition.

Call it the first D of self-storage. The other four Ds explain the moment of need. This first D explains the attachment that turns a moment into years.

Disposition is where psychology meets self-storage. Psychologists describe it as someone’s inherent and habitual way of thinking, feeling, and behaving. Part of this includes someone placing importance on things simply because they own them, regardless of value. For them, their possessions are an extension of their personality. While this concept has been studied for decades, it’s rarely, if ever, discussed in terms of self-storage. It’s time to change that.

Dr. Russell Belk, a research professor at York University in Ontario whose work explores possessions, collecting, gift-giving, sharing, and materialism, has spent decades studying why people become attached to things. His landmark 1988 paper “Possessions and the Extended Self” argues that “we are what we have,” an idea that continues to influence consumer behavior research today. In the paper, Belk reinforces this idea by observing how many people experience a diminished sense of self when their possessions were unintentionally lost or stolen.

He still discusses the topic today, having recently returned from engagements in France, India, and Brazil. MSM spoke with Belk to further discuss how his research applies to self-storage. Although the industry’s impact on keeping possessions wasn’t part of the initial study formulation—it was still a relatively nascent industry in the 80s after all—he says the ideas carry over. “The four Ds certainly can necessitate or at least urge us to use storage,” he says. “The decision to pay for it becomes less about economics and more about maintaining identity.”

Something as simple as old shoes can take up storage space if there’s enough memories attached to them. Belk recalls a study he and his colleagues did on footwear, and one ballerina stood out. “She had garbage bags full of her old toe shoes that were bloody and ripped, and they were no longer any good. But she’d put literally so much blood, sweat, and tears into them that she couldn’t fathom getting rid of them. They represented something more to her than just shoes.”

Belk explains that this personal nostalgia can be very powerful. “It’s not necessarily about wanting to go back to a particular period of time or stage of your life; these items represent a piece of you. Although they may no longer be a key part of your identity, at one point they were and they may have shaped the person you are today.”

When people anthropomorphize things, or treat objects like real beings, attachment can become even stronger. Think of children who name their stuffed animals; if you take the toy away from them, they may be distressed for weeks. “As adults, we also become attached to possessions like cars, bikes, and other belongings. Once we name them, it’s no longer just a functional relationship; it’s attachment, and that makes them harder to part with.”

Some people have such a hard time parting with their possessions that they hire personal organizers to help them declutter. Belk has done some work with these professionals to witness how people would respond to having to unburden themselves of their stuff. During the study, the organizer would ask a question such as “Does this spark joy?” If not, the recommendation would be to get rid of it. “People would comply, but there’d often be recidivism. After a year or so, they’re back to the clutter that caused them to call an organizer in the first place.”

Again, this is where self-storage comes into the picture. Operators often think they’re renting square footage, when they’re really renting something much more valuable: space to hold on to identity and avoid the emotional discomfort that comes with letting go.

While the industry has spent decades measuring occupancy, rental rates, and move-ins, beneath every lease sits a remarkably consistent piece of human psychology. People almost always value what they already own more than someone else would; there’s a name for that too: the endowment effect.

One of the most famous experiments that demonstrates this phenomenon was conducted by behavioral scientists Daniel Kahneman, Jack Knetsch, and Richard Thaler in 1990. Researchers gave half the participants a coffee mug (the “owners”) and the other half nothing (the “buyers”). Next, owners were asked how much they would need to sell the mug, while buyers were asked how much they would pay to get one. Owners valued the mug at roughly $7, while buyers were only willing to pay around $3 for the exact same mug.

That tendency appears everywhere, such as homeowners who value their house’s worth much higher than nearby comparable sales suggest. Other examples come to mind: Sellers on eBay routinely inflate the price of used items that could be purchased new for less; on “Antiques Roadshow,” people refuse to sell items when they learn they can’t get the price at which they thought an item would be appraised.

Self-storage operators see the same thing every day. A sofa worth $300 at a resale shop may occupy a climate-controlled unit for years. Boxes labeled “college,” “Christmas,” or “baby clothes” remain untouched through multiple rent increases. Even when replacement would be cheaper than continued storage, many tenants choose to keep paying. Viewed through a financial lens, the decision appears irrational. But through the lens of behavioral psychology, it makes more sense.

A storage auction, on the other hand, demonstrates the endowment effect in reverse. To the former tenant, the unit may have represented years of memories and thousands of dollars in perceived value. To the winning bidder, it’s simply a collection of objects with a resale price. The contents didn’t change; the owner did.

While the endowment effect explains why people value their possessions more once they own them, another psychological principle explains why letting them go feels so uncomfortable. Behavioral economists call it loss aversion, a theory developed by Daniel Kahneman and Amos Tversky. The concept is simple: People typically experience the pain of losing something more intensely than the pleasure of gaining something of equal value. For example, finding a $100 bill feels good, while losing a $100 bill feels considerably worse.

For operators, this is where the first D stops being about psychology and becomes economics. The same instinct that makes a tenant overvalue what is in the unit also makes them tolerate the rent going up. When a modest monthly increase sits next to the imagined cost of losing something irreplaceable, loss aversion quietly does the math in the operator’s favor. It is a large part of why existing customer rate increases—when not overly aggressive—are met with little resistance, and why a unit rented in a moment of crisis so often outlives the crisis by years. The first D does not just fill units; it keeps them full.

There’s also a theory that, while not developed with self-storage in mind, can be applied to our industry. Developed by evolutionary biologist John Maynard Smith, it’s called the Hawk-Dove Theory. Imagine two individuals competing for the same resource. Hawks fight aggressively to keep or “win” a resource, even if it comes at a cost, while doves avoid conflict, often retreating to avoid paying that cost.

In self-storage, the “resource” isn’t the storage unit itself. It’s the emotional value of possessions. Returning to the first D, the theory may look like this:

• A “hawk” tenant fiercely protects their possessions. When faced with a life event such as downsizing or divorce, this person refuses to part with meaningful belongings. Rather than selling or donating them, they rent a storage unit because the emotional cost of letting go outweighs the financial cost of storing them. In other words: “I’ll pay $250 a month before I throw away Dad’s workbench.” The storage unit becomes a way to “win” the conflict with loss.
• A “dove” tenant is less attached to their possessions. When confronted with the same life event, they’re more willing to sell, donate, or discard items. They experience less emotional conflict over parting with objects. They’re more likely to think, “I don’t need this anymore. Someone else can use it.” So, they may never rent storage at all, or they may rent only for a brief period.

Operators who understand who their hawks and doves are can make more informed decisions about when to raise rates and by how much, depending on the tenants themselves.

Long before humans had attics, garages, or self-storage units, survival depended upon acquiring and protecting limited resources. Having food, tools, and shelter were imperative for survival. Evolutionary biologists have long argued that natural selection favored individuals who were able to defend what they possessed. And, over thousands of generations, that instinct became embedded in human behavior.

That may sound surprisingly familiar. Humans routinely place greater value on possessions simply because they’re already ours. We negotiate harder when selling our own home than when buying someone else’s. We defend family heirlooms with an intensity that outsiders sometimes struggle to understand. Even children instinctively cry “Mine!” to hang onto something that belongs to them.

In other words, the instinct to hold onto possessions isn’t merely cultural but deeply biological and self-storage remains a perfect solution to this ancient conflict. Instead of choosing between throwing something away or sacrificing valuable living space, customers purchase a third option: a storage unit. They get to preserve ownership without cluttering their home or garage, they don’t have to go through the emotional discomfort of letting go, and the facility offers security, insurance, and climate-controlled units that keep the items safe (i.e., physically defended).

This is why when there’s a burglary or fire, you often see reporters interview tenants who lost all their belongings. They’re often incredibly distressed, and many will say they lost “invaluable” possessions, even if those items didn’t have much monetary value. This was just demonstrated in a recent story MSM reported on about a self-storage burglary in Issaquah, Wash. Kelsey Johnston, one of the victims of the break-ins, told reporters, “We open up the door, and everything’s scattered to the ground. Things are ripped open. It’s just violating. These are memories. These are not just things that you can sell.”