We are constantly inundated by the words of snake tongued spineless marketers and salesman that want to convince you that their particular product, which you never needed before, is something you desperately want and need to complete your life. You are in essence manipulated to feel that to not have this in your life is to be missing something fundamental.
But this is a false feeling, generated somewhere deep in your monkey brain. Never let that nonsense in.
How much of the shit you have in your house do you really need? How much of that junk you've been piling up over the years, bought on impulse, is actually making you happy? You can probably point out at least a few novelties which were interesting to you once upon a time, but now sit there collecting dust.
You don't need "stuff". You never did. Someone convinced you that you needed it. In fact, many of the things you bought have probably not even enriched your life all that much; instead, you've merely made your existence needlessly more complex, without any significant benefit to your happiness. In some cases, these purchases become a net unhappiness.
Trimming down excess consumerism is likely one of the most rewarding things you can do. It saves the environment, our time, and our precious and limited resources from being spent on wasteful, unnecessary crap. But let's just be frank, you probably don't care about that. What you do care about is this: killing your inner consumer and feeding on its corpse will make you a happier, freer, and richer person. That all goes hand in hand. Not spending excess money will allow you to put into things that matter more to you: good experiences with friends, your dreams, your investments. Not being bound to buy the latest toys which distract and chain you will free your time so that you can work on yourself. Being richer will afford you better ways to do things.
Necessary goods that you've overthought
There are a lot of modern necessities that you need, but you probably throw away money purchasing anyway.
Your absolute worst purchase
If you're an American, look no further than your car. Where in Europe many cities were built under the practical consideration of walking, biking, using public transport to get to necessary goods and services, we've quizzically engineered entire cities and neighborhoods to starve unless residents decide to strap into hunks of metal and propel themselves with explosions to a Wal Mart several miles away.
What you probably need is something very simple: a mostly reliable older device you can purchase with your savings budget that can transport you from point A to point B. What you probably have is a brand new money burning monstrosity with adjustable cup holders, bluetooth seat warmers, and voice activated truck nuts that you had to borrow money in order to purchase, will never sell for what you bought it for, and costs you an arm and a leg in insurance and wheelage taxes. You use this Superfluous Utility Vehicle to commute 1 hour to your office job because 5 years ago you needed to haul a couch once and like to have the flexibility to do that again. Plus your friends would make fun of you for owning a used Honda Fit even though it does everything you really need but is actually economical with what it does.
Yeah, that used Fit won't keep its value either, of course but it also doesn't cost more than literally everything you have in your bank account and costs you less for absolutely everything else too. Even buying two of them over the course of 14 years of driving will likely net you more money than buying that stupid gas guzzler.
Your Dumb Inner Kid
The grocery store is a marvel, and if you don't think that you probably lived a very comfortable life. It's also a place of stupidity and excess. A good half of it or more is a trap.
The key to having good tasting food are spices. They key to filling food is fats. The key to a healthy food is the produce, and a meat should be a special little addition (200 pounds a year, as most Americans eat, is probably at least double as much as you should consider for such a luxury). Besides your coffee and tea, that's all you should focus on buying.
A lot of the grocery store is filled with things that are entirely unnecessary. Things that will not enrich you, things that prey on your monkey brain's instincts and desires for easy, sweet, savory things. Or things that sound good on paper, but are overpriced and stupid. Don't get lured in to purchasing pre-processed goods.
When you take the effort to make your own food, you will be healthier, more disciplined, and self-sufficient. You will be able to experiment and make things in ways you wouldn't think of doing before. If you need something sweet, bake it yourself, and make your treat an even more satisfying reward.
Your dwelling and your job
These things are likely your worst enemy, and make your worst purchase an even worse thing to have to live with. Your commute is an affront to your time, and your money. Sitting in traffic in a car for an hour or more going to and from work is like shoveling money into a furnace. You should treat the time and expense as a direct docking of your wage. The entire system here is stupid.
Are you commuting so you can have a bigger house? How many rooms do you really need to be happy and comfortable? Are you just holding on to curios total junk in half of them? Or you could ask: Why did you pick a job that's so far from where you live?
If you could instead could move closer to your job, to some place perhaps smaller, and replace that car for a bike (or even walking), you could turn your commute into your exercise time to become fitter, while living much more cheaply and being more conscious about what you waste your money on. Unless, perhaps, you live in a place like New York or San Francisco, in which case, my condolences.
Entertaining yourself to death
Fun is fun. What is life without a little entertainment? But how are you obtaining your fun?
Is that cable package actually enriching your life, or are you just living in a world of constant distraction, pretending to be informed with useless knowledge regarding the world today and reality shows that warp your sense of reality? How much of youtube has that covered? Does any of that really even make you happy in the first place?
I'm not going to be pretentious and tell you to go to barnes and noble, or pull up amazon kindle, and read some overpriced book you'll glaze your eyes over anyway. I'm going to harshly and pretentiously grill you another way: If you keep up with passive or interactive media, because all you have in common with your friends is whatever passive or interactive media you happen to both consume, you are a boring person, and you don't actually have any friends. You just have a bunch of people you happen to hang out with, that will be gone as soon as whatever common piece of media you happen to enjoy begins to fall apart or fade away.
A cable package can hover around $120/month, usually more. Saving that $120/month instead would net you a more-or-less permanent $120/month in 15 years, and if you waited five more, double that. Consider too, the cost of a new TV every few years as they intentionally break down, or become outmoded. If you simply learned to be content without any of this needless content, you'd be far ahead in the long run, without missing all that much.
There is so much that you can experience in the world that is wonderful and interesting. Have a passion, pick up a hobby. Find people that you have common ground with doing tangible lifelong things. Those people will have interesting things to say, will help you grow, and will provide you with better experiences.
We are trained to more or less find boredom so intolerable, that we must fill the time with something that is in essence empty. But there is a benefit to boredom, which we have lost: it is the best time to let your mind wander, explore new ideas, and work on improving yourself. You can't do that if you are just consuming for the sake of consuming.
Your invisible chain
Once upon a time if someone called you, and you weren't home, oh well. A person would need to wait until you came home and answered your phone. You, on the other hand, could enjoy yourself at the local theater, or the bar with friends, or at the library deep in study, or at a restaurant with your wife for however long you deem necessary to enrich yourself.
When you went to bed, you set your alarm and went to bed. There was no need to keep the TV on or have a last minute conversation with someone miles away from you; you took care of yourself first.
Do you really need to be reachable anywhere, any time, at any hour? No. It's overly burdensome. Leave your emails at work. Leave your phone in your car or at home when you go out. There is no reason anyone should be capable of interrupting your personal time at their discretion, and there is no reason everything must be instant. You have the freedom to decline any conversation at any time. Exercise it.
Widgets for every circumstance
Tired of the tedium of peeling your grapes? Frustrated your Mexican street taco drips all over the place every single time? Do you lack the 20 or so seconds it takes to cut a whole banana?
There are a lot of things that we deal every with that are mildly annoying. There are 100 products that were cheaply manufactured for each of these niggling issues that we don't really need. There are even entire stores dedicated to gifting these crappy half-thought solutions. Particularly worthless are all the products we make for the kitchen. There is nothing these specialized products do that a more general or familiar one you might already have will likely either do satisfactorily or do even better.
If it's a two dollar apple corer, and you eat the fuck out of apples, then whatever. That's not really a purchase to fret over. But if it's anything more than that you should seriously question yourself in regards to how often you will use it, and how seriously this device will actually allow you to achieve a better life. If you have basic monetary sense, it's the moderately expensive impulse purchases that will burn you most.
Let's all consume less
Save yourself troubles you don't need, by saving. Too much of our world revolves around things you don't need, and that won't make you happy. Do more, with less. It will build discipline, make you more self-sufficient, and keep you sharp and thinking ahead, or in the moment, instead of thinking about nothing. Every bit you have that you don't really need weighs you down - financially, spacially, sometimes mentally. And makes it difficult to pivot yourself if you ever end up feeling like you're going in the wrong direction. If you made a mistake, don't worry. You can always buy it again.