Teaching my son to estimate jobs (and the $2k mistake that taught him)

Diego wanted to quote a 2,400 sqft interior paint job on his own. I let him. He forgot to account for: - The 12-foot ceilings in the living room (more paint, more time, need scaffolding) - Prep work on the old trim (3x longer than he estimated) - The fact that we'd need a primer coat on the dark accent walls His quote: $3,200 What it should have been: $5,400 We honored his quote because your word is your word. We lost about $2,000 on that job when you factor in our time. BUT — Diego will never make that mistake again. He now has a checklist he goes through for every estimate. And he learned that underpricing hurts worse than losing the job. Best $2k I ever spent on education.