Rule reminder
'Essere solito/a + inf' and 'solere + inf' are near-synonyms for habitual actions, both formal. Key differences: (1) 'Essere solito/a' requires AGREEMENT in gender/number (solito/solita/soliti/solite); (2) 'Solere' conjugates like a normal verb but has irregular forms (suolo/suoli/suole/sogliamo/solete/sogliono); (3) Both can take the imperfect for past habit. 'Essere solito/a' is slightly more accessible; 'solere' is more literary.
'I miei colleghi ___ pranzare insieme il venerdì.' (formal present habit — solere, 3rd plural) Correct?