Turning a Hobby Into a Small Business

They've invested time, too. The Millers take turns staying overnight with the dogs who are boarded. And with the demands of the business, Miller said, they don't have the time or money right now to travel to all the dog shows they used to attend.

Many owners who succeed in transforming their hobbies to businesses come to understand that it isn't a hobby anymore.

Janyce Wald has always loved clothes and fashion. After a series of mini-careers that included teaching and designing stationery, she now co-owns a Doncaster fashion studio in Denver, selling private label clothes by appointment.

Wald considers herself lucky because she's doing something she's always been passionate about. But, she said, "in addition to being clothes hounds, we're also really good businesswomen."

"The key to being successful is, this is a business," she said.