In general, it takes a long time (3)
I believe the answer is:
era
'a long time' is the definition.
(I've seen this before)
'in general it' is the wordplay.
'in' says the answer is hidden in the clue.
'ERA' can be found hidden inside 'general it'.
'takes' is the link.
(Other definitions for era that I've seen before include "Stage" , "Age of importance" , "Series of years" , "Important historical period" , "Important time" .)