The proposal outlines what might be possible within the given constraints. We provide guesstimates for time, cost (including ongoing maintenance costs) and scope.
It’s important to tell the customer that the proposal is based on the information provided in their initial meeting and will vary as new data is discovered.
Reassure the product owner that you will be working closely with one another and will re-evaluate the estimate at each stage of the process.
Do not provide dates for the work, as this depends on developer availability, which is changing all the time.
Work should not begin until the product owner signs off the proposal and provides a cost code that has enough funds available to cover the estimate. There is an 8-12 week lead in time from when the proposal is signed off.