Weeks? That's early detection; that's success :) The longest example of that who I know of is a guy who hired me around 10 years ago; at that time his company was 15 years old and he had not made any money with it. I spoke to him 2 years ago, so his company 23 years or so old; he decided to close up shop as after 23 years he found that what he did was useless and a waste of time. 23 years. 23 years without earning any(! seriously) money and chasing a product no-one (in hindsight) will ever want. That is brutal.