For me, I've actually become quite upset with buying the best tool for what I want/need to do; that was how I was able to get off the upgrade treadmill.
For example: This past summer, my friend Adam Ryman and I decided that there where two things that we needed to best equip ourselves.
And so it began. We spent most of the summer researching products, asking friends about what they liked and testing whatever we could get our hands on. Eventually, we came to our current solution(s).
1. We needed better backpacks, specifically backpacks that where better built for carrying around our laptops.
2. We both needed to have keyboards that we'd actually enjoy using and that would last a long time.
This process has really made buying things a joy, while at the same time removing the bad feeling that you get from being on the "upgrade treadmill." Become obsessed with what you're buying, checking every little detail and scrutinizing every feature. When you eventually find just what you need, it will feel so satisfying to have something that is the perfect tool for you.
1. We both resolved that the best backpack for laptops was that Timbuk2 Q backpack. Though it's expensive ($100+) it exactly fits each of our needs and will probably last for years to come.
2. For keyboards, we went different directions. He ended up settling on a Unicomp buckling spring keyboard, while I ended up buying a Das Keyboard Professional S Silent. Again, while these aren't inexpensive, they do exactly what we need and they will last for decades.
I guess it's trading one shopping habit for another, but I think this one will save you money and get you the best of what you need.
P.S.: On reddit, there's a great subreddit just for this kind of product search. /r/buyitforlife