Always evens out after a couple of dozen (6-4,5)

'always' is the definition.
(24 hours a day, 7 days a week)

'evens out after a couple of dozen' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'after' is a charade indicator (letters next to each other).
'a couple of dozen' becomes 'twenty four' (two dozens make twenty four).
'evens' anagrammed gives 'seven'.
'seven' put after 'twentyfour' is 'TWENTY-FOUR-SEVEN'.