Assuming the product works and can be used by a client, you absolutely should be marketing and pursuing signups immediately. Rarely is it ever too early if the

Assuming the product works and can be used by a client, you absolutely should be marketing and pursuing signups immediately. Rarely is it ever too early if the product at least solves some portion of the pain the client has or can give them some benefit. This is about how you sell it. Also, be cautious on spending time in development with clients that say, well if you only had feature X. That is a common way a client will try to either dismiss you or get you to do something they know other products don't do because it is so unique to them. BUT, there are also legit times that a product just doesn't solve the need unless it has feature X, usually you will hear that from many clients not just 1 or 2. Solve the "feature X" problem by talking with the client to understand what they really need. Research to see if other products in the space solve it. If you somehow are the only product in the space or any related space than it is even more critical to understand the need for X. Ask why that is the holdup, how does it make the value so much more etc. Assuming it is legit, tell them if they sign up you will prioritize that feature and give them a timeline and early preview with the ability to help shape the feature. If they still balk, they are likely not all that serious and you don't have a product market fit, at least with that client. If you have heard from many potential clients you need the same feature to make the product usable, than obviously that should hold more weight and you should be seriously considering it or how you answer that issue. At the same time, you should still be pursuing signing these clients up and moving them forward with offers that gets them on the system.