habitual(engaging in some behaviour as a habit) adjective [UK: hə.ˈbɪ.tʃʊəl] [US: hə.ˈbɪ.tʃuːəl]
regular(permanently organised) adjective [UK: ˈre.ɡjʊ.lə(r)] [US: ˈre.ɡjə.lər]He's a regular. = È un cliente abituale.
usual(most commonly occurring) adjective [UK: ˈjuː.ʒʊəl] [US: ˈjuː.ʒə.wəl]White wine is the usual companion of fish. = Il vino bianco è il compagno abituale del pesce.