Scott Case, chief executive of the Startup America Partnership, offered some unconventional advice for entrepreneurs the other day at a Washington Post conference on small business that I helped moderate.

Don’t waste your time on the business plan.

I thought he was just being provocative. After all, preparing a business plan is part of the canon of chores we are told we absolutely have to do if we are going to create a new business.

Then Bob Litan, vice president at the Kauffman Foundation, chimed in.

Throw the business plan away, he said. The business world is always changing and successful enterprises are those that learn to adapt as they go on.

It wasn’t long before the Georgetown Cupcake founder Sophie LaMontagne was piling on.

She and her sister Katherine Kallinis spent a lot of time preparing their plan.

Then they opened the doors, and learned considerably more from simply listening to their customers:

Sophie figured the most popular cupcakes would be those reliable standbys chocolate and vanilla. She never imagined red velvet would be such a huge hit, by a wide margin.

Or that customers overwhelmingly preferred getting their cupcakes in a pink box instead of a white one.

Or that you can learn an awful lot about where to open your next cupcake store by examining where your deliveries are going.

Or that striking up a conversation with a customer, who turned about to be a television producer, would lead to a hit cable show.

Simple stuff, but as I sat listening, the discussion reminded me of how we often we get distracted by worries about taxes or regulations or energy costs or changes in health care, especially here in Washington.

The real challenge for businesses is the oldest one: Finding customers!

To paraphrase Scott Case, when you have customers, the rest is just a nuisance.