
Growth Manifesto Podcast How Brands Actually Grow with Byron Sharp
Dec 5, 2025
Byron Sharp, marketing scientist and author of How Brands Grow, explains why intuition fails in marketing. He unpacks the double jeopardy law, how penetration drives loyalty, and the twin concepts of mental and physical availability. He also discusses reach, light buyers, limits of loyalty programs, and practical ways to keep brands easy to notice and buy.
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Double Jeopardy Explains Brand Size
- Bigger brands have many more buyers and only slightly more loyal ones.
- Double Jeopardy explains sales mainly by customer numbers, not extreme loyalty.
Prioritise Mental And Physical Availability
- Expand both mental and physical availability to win more customers.
- Reach is essential: you cannot grow without acquiring many more customers.
Keep Advertising Even To Existing Customers
- Keep advertising to remind customers your brand exists; email lists erode.
- Use broad, cheap media or publicity to refresh mental availability regularly.




