[TL;DR: Marketing science shows brands grow through new buyers (penetration), not by making existing customers buy more (loyalty). For most SMEs, every dollar spent chasing loyalty is a dollar not spent reaching the people who've never heard of you.]

Why Your Loyal Customers Won't Grow Your Business

Growth comes from new buyers, not existing ones. Byron Sharp's 40+ years of cross-industry data proves it. Most small business marketing is built on the opposite assumption.

Here is the belief that drives most small business marketing decisions:

Your best customers are your most valuable customers. Keep them happy. Get them to come back more often. Build a loyalty program. Reward repeat purchases. Focus on the people who already trust you, because it costs five times more to win a new customer than to keep an existing one.

I understand why this feels true. Loyal customers are easy to identify, easy to talk to, and they give you warm feedback. Chasing strangers with ads feels expensive and uncertain by comparison.

The problem is that this entire belief system is contradicted by some of the most rigorous marketing research ever conducted.

What 40 Years of Data Actually Shows

Byron Sharp is a professor at the Ehrenberg-Bass Institute at the University of South Australia. Over four decades, his research team analysed purchasing behaviour across 130+ brands in 13+ product categories, from FMCG to automotive to financial services. The findings were consistent enough to be called laws.

The most important one is called the Double Jeopardy Law.

It works like this: brands with smaller market share suffer twice. They have fewer buyers (first jeopardy). And those buyers are slightly less loyal (second jeopardy). Both penetration and loyalty decline together as market share shrinks.

Here is the part that should stop most business owners cold: when you look at the data across brands of different sizes, penetration drops dramatically while loyalty barely moves at all.

Sharp's washing powder data from the UK illustrates this cleanly. A market-leading brand had 41% penetration and bought roughly 3.9 times per year. A mid-tier brand had 26% penetration and 3.9 times per year. A smaller brand had 19% penetration and 3.8 times per year. The loyalty number is essentially identical across all three. The penetration number collapsed by half.

What this tells you is that loyalty is largely a function of brand size, not the other way around. You do not build a big brand by building loyalty. You get loyalty as a byproduct of getting big. And you get big through penetration, which means reaching more people who currently do not buy from you.

The Retention Myth Needs a Hard Look

The "5x cheaper to retain than acquire" claim is repeated constantly in marketing circles. Sharp's research found no reliable empirical support for it. It has the feel of received wisdom, which means it gets quoted without anyone checking whether it is actually true.

What Sharp's team did find is this: brands that grew, grew through penetration. IPA analysed 880 award-winning advertising campaigns and found that 82% of winners achieved growth by acquiring new buyers. Only 2% succeeded primarily through loyalty strategies.

That is not a marginal finding. That is overwhelming.

For a loyalty strategy to drive meaningful growth, you would need existing customers to dramatically increase their purchase frequency. But the data shows that heavy buyers are already near their ceiling. They naturally moderate over time. You cannot easily squeeze more purchases out of people who are already buying regularly.

Meanwhile, the pool of people who have never bought from you, or bought once and drifted, is enormous by comparison.

The Light Buyer Insight That Changes Everything

Here is the counterintuitive part that most SME owners miss.

Sharp's research shows that most brands have far more light and occasional buyers than heavy users. These are people who might buy from you once a year, or once every two years, or who bought once and have not since. They represent the overwhelming majority of your potential customer base.

Getting the large group of light users to make one additional purchase a year has more mathematical impact than getting your most loyal customers to buy more, because the loyal group is small and already near capacity.

Kahneman's research on how people make decisions reinforces this. Most purchases are not the result of deep deliberation. They are fast, context-triggered responses. When someone needs what you sell, the first brand that comes to mind in that moment is the one that wins. That is not loyalty. That is just mental availability, which Byron Sharp defines as how easily your brand comes to mind across the range of real situations where a purchase might occur.

If your marketing is almost entirely pointed at people who already know and like you, you are not building mental availability with the much larger group of occasional buyers and non-buyers. You are just reminding the already-converted.

What This Means for How You Spend Your Budget

I work with SMEs in Adelaide across a range of industries. Most of them, when I first talk to them, have some version of the same budget instinct: email the existing list, run retargeting ads to website visitors, maybe set up a loyalty incentive. These are not bad tactics in isolation. The problem is when they consume the marketing budget while acquisition gets the scraps.

If you accept what Sharp's data shows, the budget allocation should look quite different. The bulk of your spend needs to be working to reach people who have never bought from you. That is what grows the business.

Google Search Ads, when set up correctly, are almost entirely a penetration tool. The person searching for what you sell right now has not already committed to you. They are in market, looking at options, and your ad has a chance to put you in consideration for the first time. That is penetration. Every new customer you close from search was, until very recently, someone who had never heard of you.

Facebook and Meta Ads, at their best, function similarly. Broad awareness campaigns that reach people before they are actively searching. Brand building that, over time, increases the likelihood your business comes to mind when the buying moment arrives.

Retargeting and email to existing contacts are still worth doing. But if they represent the majority of your marketing activity, you are fishing in a very small pond while a much larger lake sits ignored.

The One Question Worth Asking Your Marketing

Before you approve the next campaign or set the next budget, ask this: how much of this spend is reaching people who have never bought from me?

If the honest answer is "not much," that is where the growth is being left behind.

Sharp describes brand growth as being built on two things: mental availability (being easy to think of) and physical availability (being easy to find and buy from). Google Ads handles physical availability when someone is actively searching. But mental availability, the kind that makes someone think of you before they even go looking, requires reaching people before the need arises. That is a penetration job, not a loyalty job.

Most SMEs put almost all of their energy into the people who already know them. The science suggests the growth opportunity is mostly in the people who do not.

FAQ

Is retention marketing a waste of time for small businesses?

Retention marketing is not a waste of time, but it is frequently over-weighted relative to its actual growth impact. Byron Sharp's research does not say ignore existing customers. It says that growth comes primarily from acquiring new buyers, and that loyalty programs rarely drive meaningful volume increases because heavy buyers are already near their purchase ceiling. The practical implication for small businesses is not to abandon email or retargeting, but to make sure acquisition spending is not being starved to fund tactics that feel safer but deliver less growth. A reasonable approach: treat retention as a cost-of-service (keeping customers who would otherwise churn), and treat acquisition as your primary growth driver.

Why does the "it costs 5x more to acquire than retain" myth persist?

It persists because it feels intuitively true, gets quoted by people with authority, and is never sourced back to an actual study. Sharp's team looked for the research behind this claim and found it does not hold up to scrutiny. The confusion likely comes from mixing up short-term transaction costs with long-term marketing investment. Sending an email to your existing list is cheaper than running a Google Ads campaign, that part is true. But if the email produces marginal incremental revenue from people who would have bought anyway, and the ad brings in a brand new customer, the comparison is misleading. Cost per touchpoint is not the same as cost per new revenue dollar.

How does Byron Sharp's penetration model apply to service businesses and lead gen?

Sharp's original research was conducted primarily on FMCG consumer goods, but the Ehrenberg-Bass Institute has validated the same patterns in B2B, services, and other categories. For a service business, penetration means reaching people who have a latent need for what you offer but have not yet looked for a provider, or who looked previously and chose a competitor. The goal of advertising, on this model, is to build and refresh the memory structures that make your business come to mind when a buying situation arrives. For lead-gen businesses in particular, Google Search captures active demand (people already looking), while Facebook and brand-building activities build the mental availability that shapes which businesses people consider when the need eventually arises.

If loyal customers do not drive growth, why do some businesses seem to thrive on repeat customers?

There is an important distinction between customer lifetime value (a real and important metric) and loyalty as a growth driver. A business can have high retention and still be growing, because retention is reducing churn while acquisition is adding new customers. Sharp's point is that if you compare two businesses of similar size, the one with higher penetration will tend to grow faster than the one with higher loyalty metrics, because there are more people to reach in the broad market than there are in your existing customer base. Repeat customers are genuinely valuable. The risk is treating them as the growth engine rather than a stable foundation that acquisition must be built on top of.