Many workplaces require a certain attire. You probably already own dress clothes, but someone who doesn't might have to spend hundreds or thousands of dollars to obtain clothes for their job. But I'm not just talking about just white collar positions either; construction workers, photographers, waiters, retail workers, telemarketers, etc. all have dress codes, some for safety and some to weed out "undesirables". If I can expense my ergonomic keyboard, a dock worker better be able to expense their steel-toed boots.