the shoemaker's children go barefoot; the dyer wears white hakama
Proverbial expression meaning that experts often neglect their own affairs or fail to apply their skills to themselves. Literally, 'the dyer's white hakama' (a dyer would normally wear dark, dyed clothes, but his own formal wear remains undyed).
He's a famous chef, but at home he always eats instant food. It's a classic case of the shoemaker's children going barefoot.
They often say 'doctors don't take care of their own health,' and 'the dyer's white hakama' is much the same.