It sounds like you're not producing a quote. You're making an estimate. That's the amount of money you expect to charge them when you're done. It could change b

It sounds like you're not producing a quote. You're making an estimate. That's the amount of money you expect to charge them when you're done. It could change because of additional or less time needed due to unforeseen circumstances. In this case of working from an estimate, they're taking the risk. A quote (also known as a "price") is the price at which you're doing the work. If you do the work, they'll pay you that amount. In this case, you're taking the risk of unforeseen circumstances. If it's an estimate, call it an estimate and tell them what kinds of things might make the final price different from your estimate and give examples of how much it might change. If you're giving them a quote, then do the work for that amount. If they change the project in the meantime, renegotiate the price.