Makes no difference to me at all.
My parents switch their wifi off every night (and v inconvenient it is too!!! since my kindle and phone and ipad all need to sync the book I read, in bed. haha!)
And pre Magnesium Oil my sleep was terrible at their house, just as it was terrible everywhere.
Besides, almost all houses nowadays sit in an overlapping pool of wifi from other nearby houses or businesses.
When my home wifi searches for a signal, I get a choice of 5 different ones, in addition to our own secure wifi.
So switching ours off wouldn't make a blind bit of difference to me.
wifi waves are right next to radio waves on the frequency spectrum, and we are bombarded with them 24/7