The 5 years effect

The loyalty effect mainly has its impact over a longer period of time

First of all, your customer base grows as you manage to retain more customers.

In reality, the net effect tends to be even more positive, as loyal customers create positive word of mouth and hence tend to bring in more newly acquired customers as well.  

On top of that, the revenue per customer will go up

Below you see the cumulative effect of both effects.

CL related sales as share of total sales