You have to replace to pod every three days. I tend to rotate between the front waist and, back waist, and upper thigh. When winter comes, I may try my upper arm (opposite the G7). In theory, you could put it many more places, but you need some skin fat which I lack.
I’ve never noticed the weight of the device (it holds a max of 200 units though I never insert more than 85). But I do often notice the the device itself. I brush it fairly often when it’s on the front of me. It’s not annoying just apparent.