Yesterday I spent some time to clean out my email list.
About 20% of my subscribers were orphaned. They were in the list but not subscribed to get any emails.
A good chunk were from Repeat Customer Insights. They logged into the app from their Shopify store but didn't start an account (an abandoned cart).
Others were subscribed at one point in the past and unsubscribed but for some reason their subscriber record still showed them as active but not in any lists (e.g. receiving no emails).
Cleaning up my lists got rid of those. It saved me money and lowered my data risk (a bigger cost than most people think).
This sort of regular maintenance work is needed with any automation. Even at a small scale.
Sometimes you can let maintenance sit for awhile. This cleanup sat for about six months. If you wait too long to do maintenance though, you might find the automation gets away from you and you'll spend much more time in the long-run.
Scheduling this maintenance for slow periods is best. Right now is a good time to get any of your deferred maintenance done before the busy season starts up.
Update your theme.
Upgrade your apps.
Remove dead code.
Use cohorts to find out who the best customers are in your Shopify store
Repeat Customer Insights will automatically group your customers into cohorts based on when they first purchased. This will let you see how the date customers bought would impact their behavior.