"Lengthy deliberations" means that people have spent a long time discussing or thinking carefully about something before making a decision. Full definition
Jeremy Corbyn announces changes to shadow cabinet after lengthy deliberations as he moves to quash internal disagreement (theguardian.com)
Six scientists convicted of manslaughter for advice they gave ahead of the deadly L'Aquila earthquake in 2009 today were definitively acquitted by Italy's Supreme Court of Cassation in Rome following lengthy deliberations by a panel of five judges. (sciencemag.org)
Yau and study co-author Stephanie Reich, UCI associate professor of education, found that for girls, the effort to construct a favorable image can involve lengthy deliberation and advice from confidantes. (sciencedaily.com)