Do you use software development effort estimation methods?

I recently fell into a small rabbit hole and discovered the world model-based software development effort estimation. There are various models and tools like COCOMO (and the more recent COCOMO2) and others (See 1).

So far in my professional career, mostly in Start-ups I have yet to come accross anyone using those. Is this more common in langer orgs or government agencies? Are those helpful at all? Would love to learn about your experiences.

1: https://en.wikipedia.org/wiki/Software_development_effort_estimation#Comparison_of_development_estimation_software