Worth your salt means that you deserve the pay or reward that you get. For thousand of years salt was highly prized. This 19th century expression comes from an ancient practice. The Roman army paid its soldiers partly in actual salt or in money to buy salt. Some say that they were paid in rations that were called “Sal”, which meant salt and when money was substituted for these rations, they called it salarium The word “salery” comes from the Latin word salarium, which means “salt money” If you were a loyal soldier, you were worth what they paid you.