One problem watch for with your repeat purchases is the average order value (AOV) dropping on repeat purchases.
For the most part your AOV should be holding steady or increasing as specific customers buy again and again. If it's dropping, that's a sign of a potential problem that you'll want to look into.
This is also a symptom of heavy discounts to repeat customers, some who might have bought at the regular price.
There are exceptions. If you sell something durable that needs replenishment, you'll see a higher than normal first order (e.g. buying equipment) and then smaller repeat orders (e.g. buying refills). Even then though you should see AOV steady or trend upwards in the replenishment orders.
If you need help checking the AOV on repeat orders, that's included in the Customer Purchase Latency report in Repeat Customer Insights.
Track down which customer cohorts perform the best
Different groups of people behave differently. Repeat Customer Insights creates cohort groups for you automatically to see how your customers change over time and spot new behavior trends.