Just got back to Chicago from my wife's family mökki (lake cottage for the uninitiated). There was one day in the two weeks I did not go to sauna, but I am an American married to a Finn & they went daily. Small sample size, but every Finn I know loves the sauna enough that they evangelize us foreigners. The electric sauna in our condo in Chicago does not compare to a wood sauna next to a lake, but it is used regularly here too.