When you finally scope a job tight enough to deliver and profit

I sent the proposal this morning and I knew every line of it was solid. What we'll do, what we won't, what it costs, all drawn tight. When the client asked about an extra piece, I could say cleanly that it's a separate phase with its own price, and it didn't feel awkward. The job is bounded, the number covers the work, and I'll deliver it without bleeding nights.