em casa de ferreiro, o espeto é de pau

Etymology
lit. 'in (the) blacksmith's house, the skewer is (made) of wood'. Compare 🇨🇬.

Proverb

 * 1) the shoemaker's children go barefoot

Usage notes
Used to refer to someone who, despite skilled in a craft, does not use it in their own favor, or when certain things or attitudes are missing precisely where they would be most appropriate or expected.