How do teams actually adopt commit-as-documentation practices in existing repos?

Curious about the practical side of treating git history as a documentation layer rather than just a change log. For teams that have shifted toward more intentional commit structuring, how did you handle the transition in an already-active repo? Did you set a cutoff point, retrain gradually, or enforce it only on new branches? Also wondering whether code review workflows changed meaningfully once commits were expected to carry more explanatory weight on their own.