This paper describes how Samsung prevented Apple customers it had won from switching back the next time they were in the market for a smartphone. Behavioural insight established that intent to repeat purchase was correlated with actions such as transferring content in the first 30 days of owning a new handset. The launch of the Galaxy S9 tested the theory via a content programme of videos, a website and emails to nudge new Samsung buyers to carry out target actions. Results showed programme participants were more likely to recommend the brand and to repurchase a Samsung product than a control group not exposed to communications.