For standing desks, I have had one for years. The benefits of standings sitting I think are way less than once thought, but I still like to be able to mix it up and stretch a bit throughout the day. Sitting too long makes my legs ache.
Where it was best was in my old office when I installed a Lifespan under-desk treadmill that was fantastic, but a bit loud. Too loud to use in my current office office, which is totally open (not even cubicles), and didn't fit in my home office, so I sold it. But when I had a big enough office to myself it was fantastic, highly recommended for anyone with the right space looking to stay a bit more active. Was even able to do finicky stuff like spreadsheets if you set it up right...