Typical long-standing customer (7)
I believe the answer is:
regular
I believe this is a double definition.
'typical' is the first definition.
(similar in meaning)
'long-standing customer' is the second definition.
(a regular customer)
(Other definitions for regular that I've seen before include "Recurring at short uniform intervals" , "Habitui" , "Following normal practice" , "orderly" , "Uniform, even" .)