One particular event caused me to change the way I shopped.
I had a garage sale and sold a lot of "stuff" that I didn't use. I hated selling things for 25 cents or 50 cents -- for which I spent $20.
This changed the way I viewed items when I'd be out shopping. I'd ask myself, "do I really need this -- and will I be selling it for a quarter in a couple of years?"
It worked for me!
Now, I'm at the phase of "do I really need this cluttering my life"? My answer is usually "no". Save my shekels for those things which are expensive and I really DO want which I can either use as an investment or deduction. Small ticket items to accentuate, in between those big purchases.