When building something that you believe to be a long-term project.
Start small and let a few people try it first and ask for their honest feedback.
It's going to be a mix of reactions, such as positive, negative, and suggestions for improvement.
Take note of the comments and use them to improve the current version.
This approach has been proven and tested for me, and I believe this is the way to build something with zero investors, long-term, and with no pressure project.