Bella, I work from home, with only occasional trips to the office. Heck, when I do go to the office, jeans are perfectly fine. So that's one of the reasons I love this challenge: it gives me the perfect excuse to wear dressier clothes than I might normally wear during the week... which seem silly if you are just hanging around home telecommuting or work in a casual office!
I did consider maybe I should pick a 5-day stint which included the weekend, as I'm more likely out and about doing stuff on weekends. But I decided to give myself an excuse to dress up during the week. And while working through my strategy, I realized I could extend this challenge another 2-3 days if I wanted. It's fascinating how many outfits you can get out of just 15 pieces.