The difference between a quote and an estimate lies with the fact that one is binding (a quote, providing a customer signs for it) and one is not. To make an informed decision, you need to consider whether or not you can guarantee fixed prices for materials and labor. Either way, you should clearly outline the various stages involved in the process in order to avoid any potential conflict in the future. After all, you do not want to make it out as if you are promising one price, when in reality the final price will be much higher. This will deter any potential clients from approaching you. In this case, you should consider adding an expiry date for when the offer will no longer be valid for. After all, you do not want a client to reach out to you a year after a quote or estimate after prices for products or labor have increased considerably which will result in a new quote or estimate.