I struggle with this. I try a few different things to put me off. It doesnt always work but it helps.
I walk away. Most of the time, a sleep or 2 will help me realise that I dont actually want whatever it was. The amount if times Ive forgotten about that thing I was desperate to buy is crazy!
I think "is this the best and is it perfect for what I want?". If it's almost perfect then the answer is no and it goes back. Id rather have one perfect Christmas jumper that I love wearing year after year than 6 ok ones.
Where will I keep it? Will I really want to be moving more Christmas decorations in and out of the attic?
What will I do with it? Like actually do with it. Not what do I plan to do with it.
How many hours did I have to work to pay for it? Is that bauble really worth dealing with Sue from HR for 2hrs last week?
With Christmas decorations we have a rule that my son and I can each buy one new decoration a year. I realised last year that the amount of decorations makes putting up the tree not fun. Some also got broken. This year Im going to be ruthless and get rid of a lot.
When I get rid of stuff, I try to think aboit how much it cost and whether it was a good use of that money eg did we get £5 worth of enjoyment from it. If not, then think aboit why not and what made me buy it.
Avoid TK Maxx at this time of year! It's tat heaven (and I love it!).
I know this all sounds preachy and judged, but it's only me judging me and trying to make better decisions for me.