Grouping customers by when (or how) they arrived, then comparing the groups over time: 'March's customers' tracked for repeat rate and value against January's, instead of one blended average that hides everything.
The small-business power move is cohort-by-SOURCE: do Google Ads customers repeat and refer like referral customers do? Often one channel's customers are worth double the other's at identical acquisition cost. A truth invisible in averages and decisive for budget.
No software required at owner scale: a spreadsheet of customers with start month, source, and first-year revenue answers it in an hour, once a year. That hour reprices every channel you buy.