dribs and drabs /ˌdrɪbz ən ˈdræbz/ BrE AmE noun
[ Date: 1800-1900 ; Origin: Drib probably from drib 'to fall in small drops' ; ⇨ ↑ dribble 1 . Drabs probably from dribs ]
in dribs and drabs in small irregular amounts or numbers over a period of time:
The guests arrived in dribs and drabs.