A long time for some wage slaves (4)
I believe the answer is:
ages
'a long time' is the definition.
(ages can mean a very long time)
'some wage slaves' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'AGES' is hidden within 'wage slaves'.
'for' acts as a link.
(Other definitions for ages that I've seen before include "Historic periods or prolonged time" , "Indefinitely long time" , "A long time (colloq.)" , "Long periods" , "Historical eras" .)