I used one and it didn't help. Ended up at a charity shop.
I suppose a lot depends on the cause of the aching legs.
I, certainly, would not recommend it.
From what I have read on this, from quite a lot of medical websites, they have no lasting medical benefit whatsoever, other than the sensation when the device is in use. Switch it off and you are back to square one, however Mr Botham is still appearing in the telly, telling us the opposite. I wonder how much he gets paid for what is basically snake oil, imho of course.