There's a common pattern I see with growing D2C brands: they invest heavily in acquisition when things are good, and then scramble to build retention when CAC rises and growth starts to stall.
This is backwards. The best time to build your retention engine — your email flows, your loyalty mechanics, your repurchase journeys — is when acquisition is working. When you're bringing in new customers consistently, you have a clean window to optimize how you keep them.
Retention is compounding in a way that acquisition isn't. A customer who buys three times is worth exponentially more than three first-time buyers at the same total spend. Building systems that turn one-time buyers into repeat customers is often the most efficient growth lever available to a brand.
The other thing worth knowing: retention work makes acquisition more efficient too. When your repeat purchase rate improves, your blended CAC looks better, which gives you more room to scale paid media without sacrificing margin.
If you're running acquisition at scale and haven't built out your retention infrastructure, that's the first thing I'd look at.