“Really simple stuff like having a welcome sequence when someone signs up to your email list — one, two, three, four, five different emails. When they go to your checkout page and don't buy something, you send them some emails to remind them.”

Welcome sequences and abandoned-cart emails are the unsexy retention engine

Email flows are the unsexy but highest-leverage retention play. A 5-email welcome sequence plus an abandoned-checkout flow (optionally with a discount) is what every business making real money runs — and what most indie hackers skip.