Here's a question for people who are working at a standing-level desk - how long can you actually type while standing? Do your knees and feet get tired? I'm i

Here's a question for people who are working at a standing-level desk - how long can you actually type while standing? Do your knees and feet get tired? I'm intrigued, but... I have to type a lot if I want to get paid. Perhaps a desk that can change height?