Estimation. Great if you can fix (a) who is working on it (b) the visual and technical design and (c) the scope and (d) other interruptions. You can fix those

Estimation. Great if you can fix (a) who is working on it (b) the visual and technical design and (c) the scope and (d) other interruptions. You can fix those things, have fully signed off design docs, have a CCN process for every little change etc. and watch everything grind to a halt while you deliver the wrong thing on time. I’m not saying don’t estimate. Do! Have a plan and realise it won’t survive contact with reality.