Which tasks do you always priotize if they clash? Your new clients task or existing clients?

[Btaliat]

In a situation where you have tasks from your new clients and existing clients, and you are to do one first, which one will you do? Some freelancers will prefer to do the one of the new clients first. They always believe that they need to satisfy the new clients first to appear better to them. To some, they prefer to give the existing clients the priority first. Which one as a freelancer do you think should be priotized first?