Is there a device you can wear that measures how long you're on your feet each day?

You can make one easily from stuff you have in your basement. (or at least I can because there is so much junk down there.)

I’d use a conventional mercury switch on/off wall switch in my pocket or strapped to my thigh. That would be connected to a simple battery operated timer or hour meter.
If you have a smart phone there is probably a tilt app for that, You’ll likely need to put the phone in your cargo pants packet.

^McGyver

^^Inspector Gadget

Thanks for the idea @LuckyGuy. I’ve tried using a stopwatch around my neck but it’s far too easy to forget to stop/start it, a problem I think I’d continue to have with your leg switch idea.

I was really hoping for something I wouldn’t have to remember to use. After a lot of googling there just doesn’t seem to be any such device.

@FutureMemory The leg switch is automatic. You are just using a conventional mercury switch to do the work since you likely have one already. When you stand, the switch is vertical (switch on); when you sit, the switch is horizontal (switch off).
I agree with you. There is no way I could trust myself to keep track.