Very important is the only truthful answer.
Few subjects generate as much passion in women as what to wear to work does.
The reasons for the sensitivity and the emotion are complex social and gender issues, but I think it boils down to women resisting their long history of being judged by how they look. Sadly, many women are drawn to these behaviors in business. However, it is also harmful to ride the pendulum swing to the other extreme where you are deluded into thinking that appearance does not matter. The blunt truth is that, regardless of whether you are a man or a woman, how you dress at work affects how you are perceived. How you are perceived at work affects how you succeed.