Do You Really Need a Business Plan? The experts aren't so sure--but entrepreneurs like the founders of Roaring lion energy drink say it's a must. here's how to know if writing a business plan is for you.

Starting a business was the last thing on Sean Hackney's mind when he sat down to write a business plan. Hoping to persuade a soft drink company to hire him, Hackney scripted a plan for taking on his former employer, Red Bull North America Inc. But when he showed it to his corporate attorney father and former Red Bull managing director, "they said, 'Don't send this to Coke or Pepsi. Start the business, and we'll start it with you,'" he recalls.

That was in 2000. Today, the 40-year-old is co-founder and co-owner of Roaring Lion Energy Drink, a $6.2 million company in Sun Valley, California. "We've grown the business from a $62,000 investment to the No. 2 energy drink in bars and nightclubs," Hackney says. The company has 32 employees, and Hackney's erstwhile sounding boards are now his investors and co-managers. The business plan he wrote has been through numerous revisions, and today, a regularly updated marketing plan guides the company. Writing the plan, Hackney says, was "absolutely" worthwhile. "I had a lot of stuff in my head that needed [to be] put on paper."

Clemson University entrepreneurship professor William B. Gartner believes business plans are essential. And the SBA notes on its website: "The importance of a comprehensive, thoughtful business plan cannot be over-emphasized." But lately, questions have arisen.