Almost no one knows if a project/business idea will be successful or not, so it's not much use asking. It's more productive to ask smart, experienced people how to best validate and execute an idea. People generally give useful and actionable feedback based on their experiences. Just make sure you understand who you're talking to when evaluating someone's advice.
"understand who you're talking to when evaluating someone's advice."
Good you mentioned this, found out to this is a crucial part as well: Always perceive the advice you get depending on that person's background and interests (e.g. your target group, or domain-foreign expert).
