It's usual to have an overall (7)
I believe the answer is:
general
I believe this clue is a double definition.
'it's usual' is the first definition.
(thesaurus)
'an overall' is the second definition.
(thesaurus)
'to have' is the link.
(Other definitions for general that I've seen before include "Normal; military rank" , "Usual; officer" , "Popular" , "Enlarge (anag.)" , "Not specialised or limited" .)