We want to work out a value for "Average time in service" for our users.
However, as we have many subscribers still active, how can we do that? If we just look at average time of deactivated subscribers, that won't show the picture.
Is there some "correct" way to do this? We know our churn rate by month, so maybe we need to work out from those still on the service, when they're likely to leave? and use that?