This. Fixed deadlines based on real, immutable events. My current role had flexible deadlines. It makes me crazy. All that allows for as unchecked scope creep.

This. Fixed deadlines based on real, immutable events. My current role had flexible deadlines. It makes me crazy. All that allows for as unchecked scope creep. So I can't estimate, because the teams requesting the work refuse to define a project's final state (or are incapable?) and it's often impossible to make arbitrary deadlines because they're not real either. I get almost nothing shipped. And when I do, it's literally $7k over or $6k under!