get on in years

What is the origin of the idiom "get on in years" and when to use it?

The idiom "get on in years" originated from the concept of advancing in age or growing older. The phrase implies the passage of time and suggests that a person has lived for a considerable period. It can be used to refer to oneself or others, and is commonly used in a respectful or polite manner when discussing someone's age, usually in a neutral or positive tone.