@Physlink, I leave my unit on all the time. When I first got it, I would turn it off every night, thinking it would help save the battery, but was finally told not to do that. I realize now it does need to be left on all the time. I’m sure you could turn it off for short periods occasionally, if needed, but really there is no need to.
I was told not to b/c the body needs to get used to having it, and adjust to it especially when first getting it. It’s not like you get a unit and just turn it on to work and turn it off when you want. You have to take time to find the best settings and it is recommended to try a setting for at least 3 days before changing to another level of intensity, and even longer when changing to a different program, at least that’s what I was told. From experience, it is a process to find the right settings, at least for me.