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