Not all parts of a deployment can be automated in every case. I've helped craft a checklist we use on our releases based on lessons learned over several years,

Not all parts of a deployment can be automated in every case. I've helped craft a checklist we use on our releases based on lessons learned over several years, an awful lot of it is about communication to end users / other teams. Especially if the release is one that involves downtime it's important to have consistent practices and clarity about who is going communicate what and when. Checklists are a good way to capture the "what could have gone better" outputs of retrospectives.