What Monkeys Taught me about the Real Estate Database: Dunbar’s Number Explained

Most agents don’t fail at real estate because they can’t sell homes.
They fail because they can’t track homes. Sound Bananas?

We talk endlessly about scripts, listing appointments, branding, and lead generation channels. But we rarely talk about the quiet force that separates consistent producers from everyone else: the ability to manage relationships at scale.

And scale is the operative word. Because the human brain… your brain, my brain, every agent’s brain, is simply not built for the job modern real estate demands.

The real bottleneck in most agents’ businesses isn’t lead flow.
It’s the size, quality, and usability of their real estate database.

Dunbar’s Number and the 150-Person Brain

Just a heads up, this gets really nerdy for a second, like a level 8.2 on the nerdometer  – but stick with me.

Anthropologist Robin Dunbar introduced a simple but powerful idea after studying primates for decades: humans can maintain stable, meaningful social relationships with about 150 people.

It’s the size of a community that primates, and eventually, our ancestors evolved to manage without tools, technology, or friction.

Dunbar’s 150 is your internal relationship budget.

Beyond that number, we start dropping details, forgetting names, losing context, and misplacing opportunities. Our brains just weren’t wired for more.

The problem?

In today’s real estate, 150 relationships is nowhere near enough.

The Math: Why a 150-Person Sphere Can’t Sustain a Real Estate Business

To earn roughly the average U.S. Realtor income, an agent typically needs 8–12 closed transactions per year, depending on commission norms and local price points.

But even in a healthy housing market, only about 5% of homeowners move each year.

That means for every 1,000 households, only about 50 are likely to transact in a given year.

So if your real relationship capacity tops out at 150 people:

150 contacts × 5% annual move rate
= 7.5 potential transactions per year

And that assumes perfect memory, perfect awareness, and perfect timing, none of which humans naturally possess.

Even elite coaching systems quietly acknowledge this limitation. Buffini, Ninja, and others teach agents to tier their spheres precisely because human attention is finite. The top 20–40 relationships get white-glove treatment.

But everyone else?

They fall into a long tail of people who might trust you, might use you, and might move, yet won’t stay top of mind without help.

To earn an above-average income in today’s market, most agents need a real estate database in the thousands, not the hundreds.

Which creates a structural tension:

• You’re wired for 150 relationships.
• Your business requires 1,500–5,000.

That gap is the modern real estate relationship problem.

Why Your Real Estate Database Is Now the Business

Real estate used to reward charm, consistency, and local knowledge.

Today, it rewards scale and timing.

You simply cannot nurture, update, analyze, and prioritize thousands of relationships manually. No number of sticky notes, color-coded spreadsheets, or well-intentioned coaching systems can overcome evolutionary biology.

To operate above average today, agents need a clean, centralized real estate database supported by technology that:

• Keeps contact information accurate
• Tracks engagement and behavior shifts
• Surfaces likely movers and life-event signals
• Prioritizes high-probability conversations
• Automates follow-up when agents are busy

This isn’t about chasing shiny objects or replacing the human touch.

It’s about offloading the parts of relationship management humans are bad at, so you can focus on the parts you’re great at. 

Technology becomes the second brain that compensates for the Dunbar / 150-relationship limit.
Software becomes the memory you don’t have.
AI becomes the early-warning radar you can’t replicate manually.

From “Working Your Sphere” to Working Your Real Estate Database

The industry is quietly shifting from work your sphere to:

Work your real estate database like a living ecosystem.

Modern agents don’t just store contacts. They structure, clean, and activate them.

That’s why tools that surface likely movers, life-event triggers, and valuation curiosity are becoming so powerful. When your database starts telling you who is likely to move and when, relationship management stops being guesswork and starts becoming strategy.

This is also why data-driven engagement tools, like automated home valuation emails and market insight campaigns—are increasingly effective. They give agents a reason to reach out that feels relevant, personal, and timely, instead of forced or salesy.

We break down exactly how this works in our recent post on
AVM marketing and how agents are generating conversations from their own databases.

The Agents Who Win Going Forward

The top producers of tomorrow won’t necessarily be the most charismatic or the most extroverted.

They’ll be the ones who understand this equation:

More relationships → more opportunities → more closings
…but only if you can see them, track them, and act on them in time.

We’re no longer competing with agents who remember everything.
We’re competing with agents who use systems that make forgetting impossible.

The Bottom Line

You don’t need AI database technology because it’s trendy.
You need it because the modern real estate landscape demands more relationships than a human brain can hold.

As we head into the next cycle of this industry, the agents who outperform won’t be the ones working harder or remembering more. They’ll be the ones who build systems that reduce cognitive load, keep their real estate databases accurate, and surface the right conversations at the right time.

Dunbar’s number isn’t a limitation.
It’s a reminder:

If you want above-average results, you need beyond-human capacity, while keeping the human relationship at the center.

Let me know in the comments if you agree with Dunbar’s claim, and how large your database is vs ought to be.