I came across a saying "Buy nice or buy twice" and that resonated with me. Another variation I have seen is "Buy once, cry once".
Getting cheap trash that will fall apart in a few months that you will have to eventually re-buy isn't going to help, but that doesn't mean you buy gold-plated or diamond-encrusted items. Spending a little bit more for most items usually gets you something that will work better, last longer, or both. Good quality stuff is usually backed with good warranties too.
I spend my time researching to see what product is the best for me, look for deals online, or even buy used if I have to.
Consumables are a great place to save. 99% of the time, the store brand cookie, or whatever, is mostly the same as the name brand. A lot of the time they're even coming from the same factory.
I generally only follow this for things that are luxuries anyway. If I'm buying tools I buy the cheapest, crappiest version of it I can find. Then if it breaks, it means I've probably used it enough to warrant the expensive version.