'as the old adage says' is a correct and usable phrase in written English. You would use it when referencing a popular saying or proverb. For example, "As the old adage says, 'An ounce of prevention is worth a pound of cure.'".
As the old adage says: garbage in, garbage out.
As the old adage says, actions speak louder than words – and feeling or expressing concern about the environment doesn't necessarily mean that a person will act on that concern in a concrete way.
As the old adage says, "There is more than one road to Rome".
He became, as the old adage says, a jack of all trades and a master of none.
As the old adage says: "When the law is on your side, you argue the law.
As the old adage says, "Change is the only constant in life".
The old adage says, "As a man thinketh he doeth".
"As Ohio goes, so goes the nation," the old adage says.
While the old adage says you get what you pay for, Mr. Malkiel argues the opposite.
The old adage says that history is written by the winners.
THE FORM BOOK The old adage says that the form book goes out of the window on derby day - and that is probably just as well.
I love the desktop app, it’s always running on my Mac. Ludwig is the best English buddy, it answers my 100 queries per day and stays cool.
Cristina Valenza
Retail Lead Linguist @ Apple Inc.