Business plan? Maybe a waste of time. Executive summary (i.e. ~5 page-equivalent of a business plan)? Well worth it.
But the value is in writing it, not in having it. At the very least, write it and then throw it away so that you don't get tunnel vision. Definitely don't go trying to farm that part out.
I hear a lot of people say they don't have any sort of executive summary or formal plan, because they think it's a waste of time. That's a convenient excuse to build something without having to think it through. That's fine if you're just building it because you enjoy it, but don't try convincing me it's a serious business.
On the flip side, I've also seen plenty of "idea" people who have only a business plan and nothing more, and then they spend all of their time trying to find someone to build it for them. That's even worse, because at least the builders, though they may not have a viable business, have something of value to show for their work.
I hear a lot of people say they don't have any sort of executive summary or formal plan, because they think it's a waste of time. That's a convenient excuse to build something without having to think it through. That's fine if you're just building it because you enjoy it, but don't try convincing me it's a serious business.
On the flip side, I've also seen plenty of "idea" people who have only a business plan and nothing more, and then they spend all of their time trying to find someone to build it for them. That's even worse, because at least the builders, though they may not have a viable business, have something of value to show for their work.