waste your breath

waste (one's) breath

To talk of, discuss, or say things that are likely to be ignored or are in vain. Don't bother trying to change my mind about this, you're wasting your breath! It looks like I wasted my breath trying to pitch my idea to the board of directors.
See also: breath, waste
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

waste your breath

talk or give advice without effect.
See also: breath, waste
Farlex Partner Idioms Dictionary © Farlex 2017

waste your ˈbreath (on somebody/something)

speak to somebody or about somebody/something but not have any effect: Don’t waste your breath on her. She doesn’t take advice from anybody.I feel like I’m just wasting my breath trying to explain things to him.
See also: breath, waste
Farlex Partner Idioms Dictionary © Farlex 2017
See also:
References in classic literature ?
You waste your breath. Stay here while I go to my man.
DO not waste your breath. Wayne Rooney plays, Wayne Rooney starts.
Don't waste your breath, they're just paying us lip service.
Trevor Fenton Jason Williams Lee Thomas Iain Lissaman Gail Brannigan It won't happen, so I shouldn't bother, you need high influence and lots of cash, so don't even waste your breath. There is no business plan, he has no options, it's a waste of press paper and time and if anyone has donated can you lend me a grand please I promise to give it back tomorrow lol I'm sorry, but his website is hilariously bad, and he's expecting people to put PS3million in a big hopeful pot through it.
ES, Llandaff, Cardiff LINDA SAYS: Don't waste your breath on keeping the lady informed.
So, by all means, marvel at the whole bejewelled shooting match, but don't waste your breath asking yourself why something like Meydan can't happen here.
Don't waste your breath on faces who you know are gossiping for the sake of it.
Don't waste your breath, Gareth Thomas, by asking people not to "throw mud" as if you were some bunch of poor, hard-done-by fellows.
So please, direct your campaign at the administrator and the Football League, if necessary, but don't waste your breath or time on anyone at Sisu.
And especially don't waste your breath pretending you're not going to watch it this year.
The President, exiled in 1973 but now pardoned said: "The answer is no - so don't waste your breath. We're going there for a good fight - and remember I'm a general."
But as they can't, or won't, then don't waste your breath on them.
So if anybody wants to point out that, in paragraph 2, 'The way you do' is a subordinate clause and should not begin with a capital letter, don't waste your breath. I know that.
I WOULDN'T waste your breath because he doesn't want to listen.
VEGAS is great, but don't waste your breath trying to crack any jokes - no matter how feeble-with taxi drivers.