More than ten years ago, ProZ.com released an online rates calculator designed to help you determine the minimum rates required to meet your objectives. Together with forum discussions, the record of average rates reported by the community, and other useful resources such as the the article "Determining your rates and fees as a translator", the rates calculator has proved to be very helpful in answering one of the questions asked more frequently by freelance language professionals: what rates should I charge for...?
As a freelancer at ProZ.com, you have the option to include rates. Some do, some do not.
In a previous Facebook group discussion, Andrew Morris suggested that he always preferred not to in the early days when seeking out new clients all the time, because some clients surprise you by offering you more than you’d have naturally stated.
That seems like a simple explanation for one side of the debate.