'Let sleeping dogs lie' is a well-known expression meaning you shouldn't disturb a situation as it would result in trouble or complication. I think it should officially be changed to 'let sleeping babies lie'.
Seriously. They say you should wake babies to eat every three to four hours, but when they look like this before:
and they look like this after, why?
If this installment of `before & after`doesn't convince the world to change the expression I don't know what would. I, for one, will be letting sleeping babies lie more often from here on out.