For repeat customer performance, Profit from repeat customers is the best metric to watch.
Being based on profit, it's a core business metric. Direct costs to acquire repeat customers will tend to be lower than new customers. Indirect costs could be higher as repeat customers could use a greater portion of overhead costs as your loyalty, retention, and other programs are long-lived before you see a repeat order.
You'll know the process is working well as long as it's positive, trending up, and a good enough business return.
If costs are difficult to separate and calculate for repeat customers, revenue from repeat customers is a good alternative. As long as you watch your expenses and margin, segmenting your revenue into new/repeat customer can show you the health of your business as a whole.
Eric Davis
Segment your customers automatically with RFM
Segmenting your customers has always been touted as a powerful marketing tool but many stores avoid it because it can be time-consuming.
Repeat Customer Insights will automatically segment your entire customer base for you based on the valuable data Shopify has already collected for you. Ranging from 5 to 30 to over 125+ different segments using RFM and other models, you can pick how much power you want to harness.