01 · 1 MIN READ
Ranges, not numbers
A single number is a promise. A range with the reasoning attached is information, and information is what a client actually needs in order to decide.
“ Six weeks if the payment provider's sandbox works as documented, and ten if it does not. ”
- State the assumption that would move the number most
- Timebox the unknown before estimating around it
- Re-estimate after the first spike, in writing









