Repeat Customer Insights has included a customer grading algorithm for awhile now to help translate the complex RFM model into something easier to understand.
Since it uses five segments, it's also useful for small Shopify stores who don't need or want a complex model.
I've just released a new Customer Grading Report for the app that will summarize how your customers are graded by the algorithm.
This combined with the grading details for each customer should give any Shopify store the ability to get started segmenting customers.
If you haven't tried Repeat Customer Insights yet, it comes with a 14-day free trial so you can see how it helps before paying.
Discover where your best customers come from
Going beyond simple attribution, Repeat Customer Insights lets you analyze and segment your customers by who first sent that customer your way.
This will let you find the best sources of long-term customers, not just anyone who orders.