Spacing Out Oops! Forgot to include something crucial in your business plan? So did these entrepreneurs.

Are you sure your well-thought-out business plan covers all the bases? As these entrepreneurs learned the hard way, something vital could be missing. Here's what they forgot-and what they learned from their mistakes.

• "We forgot to plan for the obvious, like who would watch our kids and clean our houses while we worked 18-hour days. And we should have included a chapter in our business plan about the effects of sleep deprivation on wholesome snack production. These are things you think you'll just figure out as you go but should really be discussed in the planning stages."

-Lisa Coates, 35, who launched Monkey Muffins, a Nyack, New York, maker of wholesome children's snacks, with partner Robin Rarrick, 42

• "My business is in New York City. However, when I compiled my annual financial projections, I did not include New York City's tax rate in the business plan's annual tax calculation. This made it more difficult for us to reach our annual net profit goals. Fortunately, in 2003, we exceeded our net profit by 3 percent-after paying the [city] taxes."

-Clay Siegert, 29, who launched board-game business Intellinitiative with co-founders and siblings Anne Siegert, 27, and Evan Siegert, 25

• When Tom Szaky set out to produce an environmentally friendly way to handle garbage, the idea didn't quite work out as planned. The plan was to have worms consume the garbage-and it worked, until he and his business partner realized they hadn't factored in the huge amount of worm excrement they would have as a by-product. "Only at the end [did we realize] it could grow plants well. The liquid [fertilizer] turned out to be profitable, and [that became the core of the business]."

-Szaky, 22, who founded TerraCycle, a Princeton, New Jersey, company that makes products out of waste materials, with Jon Beyer, 21