While I imagine we had at least one around the house while I was growing up, I don't remember ever using anything but an electric heating pad. I've never even owned a hot water bottle and I'm in my 50s.
According to my Internet research, the hot water bottle was invented in 1903 by a Croatian, Slavoljub Eduard Penkala (Budapest, Patent No 29276). Electric heating pads were invented in 1912 by an American, S.I. Russell, to warm patients suffering from tuberculosis.
My personal favorite for at least 15 years has been this microwave heating pad that feels as though it is filled with sand. I am going to make these for gifts someday, but will have to open a seam on mine to inspect the contents. I bought it at a craft fair and it's long and skinny and wraps cozily around the neck. I am prone to back spasms and it is great for fitting into just the right sore muscle and stays warm for a good long time.
But, back to my original thought? Does anyone still use old-fashioned hot water bottles?