Siciliano Cu mancia fa muddichi. Literal English A person eating must make crumbs. To make an omelette, you have to break a few eggs. An apple a day keeps the doctor away. Chi causa del suo mal pianga se stesso.
Necessity is the mother of invention.
In casa di ladri non ci si ruba. There is honour among thieves. Nessun posto bello come casa propria. Niente uccide piu della calunnia. You'll never know till you have tried.