Deepak is right about using FIXED LOD at the level of [Driver ID].
It is how the Lifetime would be defined that makes a difference.
Having the [Driver ID] in the data would allow calculating their lifetimes directly.
The AVG Lifetime per Driver is a simple aggregation of the values for each Driver.
The fine point is to define a proper Recent Date Period (as a filter)
to exclude the latest / newest Drivers that have Rides in the Recent Period.
One couldn't count those Drivers as Churned,
so their Lifetimes couldn't be taken into account.
Please find the attached as an example illustrated the above logic.
Lifetime_Value_v10.2_YF.twbx 9.2 MB