I’m not talking about a deadline. You have tell the client when you can deliver the finished product. But, you should not tell the client how long it takes you to actually do the work. You may say you can deliver a project in 14 days. It may only take you 3 hours to actually complete the project. The client needs to know about the 14 day turnaround. They don’t need to know that it takes you 3 hours of your time to do the work.