I just did this (turn mine off) after leaving them on for several months, and it was at least 24 hours before all was well again. During that time the sound seemed a little closed in, rough around the edges, but still very good. It's really nothing to stress about.
Lots of threads about it already on this circle. Many different opinions too, but you won't get a definitive answer. I just followed Klaus's advice and it seems to work for me.
Tom