It’s time to revise our view of business planning and recognize that not all business planning is about proving that a market exists, so outsiders (like investors, for example) can understand the market need and believe in your business.
Quite often you’re working with businesses you know, markets you already know, and market information you won’t use anyhow, because you’re going to trust your instinct, and do what you think will work. You know the business and you’re going to take the risk.
I’m not advocating ignorance, but the vast majority of new businesses are small businesses started with small amounts of funds. Usually you know your business, you pretty much know what you want to offer and to whom. If that’s the case, don’t let the market research bog you down. Get on with the business.
The value of information, in business, is to influence decisions. If you know what you want to do, and you don’t have to prove the market to anybody else, then do it.