Average time between emails

hello Anonymous 

please check if this accomodate your need.

1. create a new measure for calculating 'Get Time from Previous Email'

Get Time from Previous Email = 
var _ID = SELECTEDVALUE('Table'[email_ID])
Return
MAXX(
    FILTER(
        ALL('Table'),
        'Table'[email_ID]<_ID
    ),
    'Table'[received]
)

2. create a new measure for calculating 'Time Difference' since you want to see the average time

Time Difference = 
var _Received = SELECTEDVALUE('Table'[received])
Return
DATEDIFF('Table'[Get Time from Previous Email],_Received,MINUTE)

3. create a new measure for calculating 'Average'

Average = AVERAGEX('Table',[Time Duration])

4. to get average time for each customer, create a slicer with customer as the value.

Hope this will help.

Thank you.