One of the primary functions of your business should be to keep customers you've already won.
Existing customers are easier to entice to buy again (e.g. 27% vs 3% conversion rates), they spend more, and you've already built-up some measure of trust with them.
Every week you need to be thinking of how you're going to improve your relationship with them. It could be simple like an email newsletter for customers-only. It could be part of a 34 component retention and loyalty system. Use whatever you can based on your business resources.
But at least every week you should do something to keep them interested in your store and products.
If you haven't installed Repeat Customer Insights yet, it's an easy way to get a detailed look at your repeat customer behavior.