Something that me and my wife have changed radically on the last 2 years is buying expensive high quality products.
In the first 4 years of being together we bought 3 very shitty Walmart vacuums. They were absolute crap at actually sucking dirt up. Ultimately, they would break very fast as well.
We decided to give a higher quality vacuum a try even though we cringed at the price. Wow, what a difference. Not only do the vacuums work 100x better (not exaggerating) a secondary effect is they work so well that my allergies have gone down drastically.
We've realized that by front loading the cost we are usually saving 2-10x over the decades.
What are some products you've bought that have been extremely high quality and that will end up saving you money over the long term?