I do contracting and handyman work, so I have different outfits for different jobs. Slacks and a polo with company logo when meeting with clients, making bids, etc.; jeans and t-shirt on drywall, roofing, framing jobs and the like; painter's blues; a crawlsuit for entering crawlspaces; and back to the slacks and polo for electrical work (plastic buttons rather than metal you find on jeans, plus a contractor I used to work for taught me that you encounter a different set of customer expectations when doing electric work.)

Aside from that, I have three tool belts so I can have different rigs for different jobs rather than carrying around a whole lot of stuff I don't need. Then there's various safety equipment, again depending on the job.