A bra worth quitting your job over?

Don't quit your day job ... yet. Or, at least wait until you talk to Carol Roth, a small-business advocate, "recovering" investment banker, and author of "The Entrepreneur Equation." In a new digital series, Roth takes on would-be entrepreneurs who want to abandon their careers for new small-business ideas. Here, she analyzes Madhavi Jagdish, a web designer for the shopping site Wanelo, who had an idea for a better bra and launched Simple Bra in her spare time.

While most entrepreneurs start with what they believe to be an amazing idea, execution almost always trumps ideas. You can have the greatest product in the world — one that solves all kinds of customer problems — but if nobody knows about it, your business is not going to be successful.

Now, if you are part of the population that doesn't wear one, you may not know that the brassiere (aka, the bra, over-the-shoulder boulder holder, flopper stopper, etc.) is a product that could use a lot of improvement. It is very difficult to find bras that are comfortable, fit well and are aesthetically pleasing (at least to the wearer). So, you might think that it would be the perfect product for an entrepreneurial endeavor. If you can solve its inherent problems, girls (and their "girls") will be lining up around the block to buy them.

That's what Madhavi Jagdish of Simple Bra thought as she decided to solve her own problem of finding the perfect bra as a side project (or "jobbie" as I call it — a combination of a job and a hobby) while she continued her lucrative job as a UX (user experience) designer in San Francisco. She grew up in India, wearing really comfortable cotton, wire-free bras. When she moved to the U.S., she couldn't find a bra she liked — they either had too much underwire, too much padding or were just generally uncomfortable. So, she designed her own bra, the Simple Bra, which sells for $39.

She picked a tough market to get into. First, there are many well-funded competitors. Covering every price point imaginable, giant competitors dominate this multi-billion-dollar market. From Victoria's Secret and Hanes (that has brands like Bali, Maidenform and Playtex), to La Perla, store brands and more, there are tons of bra makers available that spend a small fortune to reach the consumer.

So, with a limited budget, a start-up like Simple Bra is already entering murky waters when it comes to customer acquisition. Then, factor in that when a customer is reached, the small start-up only had one style of bra to offer. This means that even if a customer liked the bra, she may not buy multiples because of the lack of styles, colors and materials available for different occasions (work, after work, way after work, if you know what I mean….). Plus, she has to be funded to carry many sizes, even in one style, because when it comes to bras, one size does not fit most.

Lightly padded and wire-free bra featuring an image of the Carina Nebula.
Source: SimpleBra
Lightly padded and wire-free bra featuring an image of the Carina Nebula.

Not to mention that, given how hard it is to find a bra that fits well, most women want to try before they buy. That makes an online-only model challenging and customer-acquisition costs even more expensive.

Those issues are part of what was working against Simple Bra, leading Madhavi to only sell around 100 bras in her test of the concept.

If you want to compete in a market like this, you better have the ultimate solution that has customers lining up and enough cash to get to the consumers in the first place.

The bottom line (or in this case, the top line) — Don't quit your day job … yet.

If you're an entrepreneur looking to turn your hobby or "jobbie" into a full-time career, we want to hear from you. Email: AskCarolRoth@cnbc.com.