I have problems with this with husband! He is getting better, though. I ask him to answer if he really needs the item NOW, TODAY, or is it something he's likely to use later. If he doesn't need to use it TODAY or RIGHT THIS MINUTE, I remind him that we can come back when he does need it, and that the money would be put to a better use on something else, like, oh, the RENT that's due TODAY.
He's getting better about my logic and seeing that I'm not trying to deny or punish him. Which is usually what escalates into a war if that's how he takes it.
Before he was on medications, I once got tired of arguing why we couldn't afford an above-ground jacuzzi. (We would need to have a concrete foundation poured for it, a fence around it (since we have an unfenced yard), electrical run to it, and a permit for it all, not to mention the cost of the unit and the maintenance. So I finally rolled over and let him buy one. He gladly signed the contract for the financing, etc. Then I told him HE needed to get the bids for all the other work that would need to be done to get ready for the unit to be delivered. Once he actually got into gathering the numbers and adding things up, he realized what a huge mistake he'd made and that we truly did not have the money for the thing. (It was going to be several thousand dollars more just to get the unit set up).
Then he had the audacity to get MAD at ME for letting him sign the purchase contract!!! Fortunately, we were still within the recision period for the agreement, so he was able to call and cancel it before we actually took delivery. I think he learned an important lesson to be careful what he asks for in the future! And to TRUST my judgement