Ja no michi wa hebi. Tamago to chikai wa kudake-yasui. Muri ga toureba douri hikkomu. Issun saki wa yami. He o hitte shiri tsubome.
Experience is the best teacher.
There is no rest for the weary. Two heads are better than one. Don't spit into the wind. Don't cut off your nose to spite your face. Don't look a gift horse in the mouth.