Under Promise, Over Deliver – Always be conservative in your estimates and promises; then deliver more than what is expected.
Customers often must make decisions based on what you say, not on your actions. When you make a proposal to the customer, they must trust you can deliver stated results in a specific time frame and at a specific price. Not only must they decide whether your proposal will likely solve their problems, but they must also decide whether you can deliver.
If you consistently miss any component of your delivery, the time, the price or the promised results, the customer will learnt o distrust your proposals going forward. You will be required to more vigorously defend your promises, if you are asked to provide a proposal at all.
If however, you consistently deliver on your proposals the customer will more likely accept them at face value. The work can proceed quickly and the customer will achieve their results more quickly.
At times, unforeseen challenges appear. If we need flexibility in delivering what we promised, our reputation for delivery will determine the allowances we are given. If we often miss the mark, there is little chance we will be given the opportunity to continue forward. However, if we have always provided the stated or even better results than requested in the past, we will most usually be given the latitude needed to succeed again, regardless of the challenge.