Quick inspection when done
I believe the answer is:
once-over
'quick inspection' is the definition.
(I've seen this before)
'when done' is the wordplay.
'when' becomes 'once' ('once' can be a synonym of 'when').
'done' becomes 'over' (I've seen this before).
'once'+'over'='ONCE-OVER'
(Other definitions for once-over that I've seen before include "Quick appraisal" , "Cursory examination" , "Quick survey" , "Quick examination" , "Rapid inspection" .)