If you have to invent a reason you needed it, you didn’t need it.

Justification that arrives after the decision is a sign the decision came from somewhere else. Real needs do not require an argument, they present themselves, and the elaborate case you are assembling is being built to quiet something. That is not a moral failing. It is how wanting works, and it is far easier to catch than to resist.

When you notice the reasoning start up, put the thing down and give it a day. If you still want it tomorrow, decide plainly that you want it, which is allowed. The problem was never the purchase, only the story attached.