It's good to have had a long life (7)
I believe the answer is:
innings
'it's good to have had a long life' is the definition.
(a good innings is a long life)
This is the entire clue.
(Other definitions for innings that I've seen before include "Time spent at the crease" , "cricketers must have" , "Batting stint" , "part of cricket match" , "Period of batting in cricket" .)