Numbering leaves people getting one break in retirement (10)
I believe the answer is:
pagination
'numbering' is the definition.
(thesaurus)
'people getting one break in retirement' is the wordplay.
'people' becomes 'nation' ().
'getting' is a charade indicator (letters next to each other).
'one' becomes 'i' (Roman numeral).
'break' becomes 'gap' (a gap is a break in something).
'in retirement' says the letters should be written in reverse (retire can mean to go back or backwards).
'i'+'gap'='igap'
'igap' back-to-front is 'pagi'.
'nation' after 'pagi' is 'PAGINATION'.
'leaves' is the link.
(Another definition for pagination that I've seen is " marking numbers on documents".)