Better to wash an old kimono than borrow a new one.
More Japanese Proverbs:
A single arrow is easily broken; a quiver of ten is not.Japanese
The plagiarist turns the body inside-out and changes the bones.
Japanese
Quiet worms will bore a hole in the wall.
Japanese
Walls have ears, paper sliding doors have eyes.
Japanese
The other side also has another side.
Japanese
Wisdom is lost in a fat man's body.
Japanese