With all these new tight builds and old builds becoming tighter with foam, I fear we're heading back into the mold'en days of old.
Not many people invest in the required exhaust fans to remove moisture from a house that is no longer vented.
I argue with the Mrs. as she doesn't understand why I leave the bathroom fans running longer than SHE THINKS I should... I should just put them on timers on days that she's working...
... she keeps closing them out of habit.