My wife and I both have fitbit flex's and we have the fit bit scales although we are all scared to get on it!!
Sadly at the moment mine is lying next to the bed, but only 2 more weeks before hopefully I start walking again!!!
I am going to try going to work next week (1 day at least) so I might put it on see how many steps I do while on crutches!!
We usually wear our Fitbit's 24/7 but I take my watch off, so to me there are different devices and not sure combining them works especially if the watch gets too big.
Still waiting for my Pebble, but still don't think I'll wear it at night.