How to Make Intelligent Decisions
We all want things. As humans, specifically, we want more things. It's arguably one of the reasons that homo sapiens (modern humans) dominated over our ancestral homo erectus (Neanderthals). From an evolutionary perspective, constantly striving the have more, be better, stronger, and more successful than those around us has allowed us to accomplish some great things. Evidence suggests that Neanderthals were more peaceful creatures, had a diet that consisted more of vegetables and roots, and tribes and families seldom warred with one another. The lineage of modern humans were more dumber and more violent. We essentially hunted the Neanderthals to extinction and became the only humans in the world. We have built cities and empires, defeated enemies, and become the global dominating force for which every species fights to become. But it isn't all peaches and ice cream.
Unfortunately, when such a behavior of demanding more more MORE all the time is hard wired into our physiology, it makes for a short stick when it comes to being happy and content with what you already have. Welcome to the plight of the modern human: finding peace and contentment among a species that thrives off of never having enough, and, indefensibly in the western world - a society and culture that is driven off of that desire.
On the other hand, we have the ability to reason with ourselves, and change our minds regardless of what the primitive parts of our mind suggest we need. It's what separates man from beast - reason, self reflection, meta-cognition (thinking about your thoughts) , and meta-meta-cognition (thinking about how or why you're thinking about your thoughts).
Always consider that it might not explicitly be you that is the driving force behind a decision you have to make, but rather your instincts and conditioning that are driving both the desire and the decision.
The key in making intelligent decisions is to always make sure that your desire isn't being driven by vestigial mental traits - that desire being to get more when you don't need it. This could be applied to saving and purchasing a larger house, buying a new car, or consumerism in general.
I put down an automatic vegetable chopper at a yard sale this weekend because although I wanted it, and wandered around a little while looking at other stuff with it in my hand, I decided that I already have a knife and I am perfectly capable of chopping my own vegetables when I need to. I also don't have to disassemble and reassemble a device every time I chop onions now. Double win. This of course is a micro example but extending it to other more costly scenarios is just as simple, and requires little reasoning to come to the same conclusion.
Suppose you want to get a better car, one that will cost you $5,000 after your current vehicle trade in. If you can get a reasonable interest rate, such as 4%, then monthly payments on a 36 month term will probably be about $145 per month. Not bad, right? But then you consider all of the financial advice you've ever heard, and perhaps come to the conclusion that even a tiny amount of debt is still not worth having. The benefit that the car brings you will be little to none over your current vehicle, and now you're paying 145 a month for something that in essence does the exact same thing as your current one, only it has a better paint job. You've just eliminated the desire from the root that was motivating you to get a new, shiny, different possession. The dissatisfaction with your current vehicle wasn't even driven by a value that you hold close to your heart - it was driven by a conditioned response given to you by society and your dumb proto-human brain.
Is this thing going to make my life better in a tangible, measurable way?
If the answer to that question is no, then you have already reached a conclusion as to if you need it or not. Ultimately you want to exercise reason whenever you can, and not make instinctual or impulsive decisions. When you actually stop and think before making a decision, you're almost bound to make the right call. When you ask yourself the simple question above, you may find that there are very few things you can purchase that actually have a measurable and lasting impact on our well being or happiness. I've heard that there is only a mind correlation between money and happiness once basic necessities of living have been covered. This is to say that so long as you have a roof over your head, regular supplies of food, and water, the amount of money you make on top of that only gently impacts the day to day happiness of each individual person.
Question everything, and you will make better decisions and be better off.