I've been using a mix of standing and using either a high drafting school or a geek desk with a firm chair for about 2 and a half years. I never have back pain

I've been using a mix of standing and using either a high drafting school or a geek desk with a firm chair for about 2 and a half years. I never have back pain like I used to and never have foot or ankle pain. Whenever I get uncomfortable in any way, I switch from sitting to standing. I figure this is a pretty good sign from my body that I could use a change. That said, the first week of standing including some restlessness and foot/calf pain. This went away pretty quickly. Additionally, I've used a GelPro mat at both workplaces with standing desks.