Let's say you would like to control your computer partly with your feet: how do you go about it? This wasn't something that I was especially interested in before my wrists started hurting, but now I have it set up I like it a lot and I would definitely keep it even if my wrists were completely better. I have three pedals, set for scroll down, scroll up, and "archive this email message and take me to the next unread message." You could possibly use foot controls for different things in different programs, but I haven't gotten into that.

I got a cheap no-name three pedal foot switch for $35 shipped. I suspect it's not the most durable option, but it's cheap enough that if it breaks I can easily replace it. It comes with (useless-to-me) Windows-only software to program it, but out of the box the three foot switches send a, b, and c. I installed the open source tool Karabiner-Elements to remap them. First I needed to tell Karabiner to only affect the foot pedals:

USB vendor id 1452 (0x5AC) is Apple, so I could tell that the foot pedal was the remaining device. Then I needed to configure what I want it to happen:

The reason for using open square bracket ([) is that it's the gmail keyboard shortcut for "archive this email message and take me to the next unread message."

By itself this is definitely not enough to make my wrists happy again, but it takes a substantial load off them, and lets me handle my email mostly hands-free. If I had a one-off repetitive task I needed to do, I would consider setting up a temporary remapping just for that task. At some point I also might consider setting up something to let me use this hardware to control my rhythm stage setup.