You should always agree on a detailed budget and estimated timeline before you sign a contract with a professional pool builder. Obviously, unforeseen factors can alter the schedule and sometimes impact the budget. For example, weather, customer change requests, permit delays, etc. can all affect the project, but a good builder will communicate and coordinate with you throughout the project to ensure successful pool construction and complete customer satisfaction.
Never be afraid to ask your builder: Are we still on schedule? Are we within budget?