Expressing an opinion is free. Everyone will tell you they think your idea is good. That’s not the same as giving up something to read it or listen to it or purchase it. Focus groups, surveys, polls, and research can’t tell you as much as putting a product or idea out into the world. In a marketplace where people have to trade-off other opportunities to take advantage of what you’ve made, you’ll learn more about its value than any test-case or lab experiment.
It doesn’t mean you can’t gather some facts or be informed. But it’s more important to have a sound theory, and a clear bet on what gap you’re filling or value you’re creating than it is to have a lot of cost-less expressions from disinterested parties of whether or not they imagine it will be valuable.
Do it if it’s valuable to you and if you believe in your unique vision. Do it if the process of answering the question, “Is this a good idea?” is exciting in and of itself. Do it if you’re willing to fail to get the answer.