Proper air pressure in one’s car tires can increase fuel mileage, if the air pressure is not too low, because there is more rubber hitting the road, and thus slightly more work for your motor to do. This is not something that most drivers give a shit about, because most people think of their car’s maintenance in simple terms: Does it work or not. Regretfully, I am not most people.

I am also not a wrencher, mostly because I don’t have garage space, because I live in New York City, which is a different discussion. But the aspects of my car’s maintenance that I can control — , general cleanliness, windshield wipers, etc — I treat with a certain level of obsession, when I’m not ignoring them entirely. The tire pressure I never ignore, though, mainly for reasons of stinginess. There is a fairly cheap way to improve my gas mileage? In this economy?

What this means in practice is checking the pressure each time I fill up, and, usually, adding some air to my left rear tire, which is the one that always seems to lose pressure, especially in cold weather, while the other three tires always seem to be close to fine. I explained the problem to the tire man last time I had them rotated, and he said there were no issues with the tire that he could see, and that this happens.

It is probably not a problem with age, as the tires are only three-and-a-half years old. I also don’t drive as much as I’d like because I commute to work in a subway car, so the problem isn’t exactly urgent. I’ve also driven my Honda Fit to California and back twice; I’m not worried about tire failure at speed. It is mostly just annoying: every few weeks I’ll check the air pressure and often times it will be low in that particular tire and then, again, I’m back stuffing a dollar in quarters (sometimes even more!) into a shitty, possibly broken air compressor at a gas station that smells.

Which is a long way of saying that, last week, I finally bothered to order a portable air compressor that I could keep in the car. If a tire needed air, I could fill it in my parking spot on the street. After some Googling, and also some sifting through some reviews sites on the internet — Wirecutter, for example, a machine called the Viair 77P, which is hard to find in stock — I settled on a portable compressor called the EPAuto 12V DC Portable Air Compressor Pump, which Wirecutter didn’t recommend even though they say it “has one of the more accurate gauges, a very low noise level, auto shutoff, a clever design for storing the hose, and an accessible price.”

They were right about the price, coming in at $35 including taxes, an amount more or less what a friend recently paid for small hand air pump for bike tires, which is a pump you power with your hands. The EPAuto 12V DC Portable Air Compressor Pump plugs into your car’s cigarette lighter, with a cord long enough to reach all four wheels.

( There is nothing to disclose because EPAuto never gave me anything and until recently I had never heard of them. Would I have accepted a free model to “test” from them? Probably not, as I’m a grown man who would rather make buying mistakes on my own. Also, who the hell wants to test a bunch of portable air compressors? Life is short. This is also not a recommendation of EPAuto’s portable air compressor; I’m assuming they are all largely the same.)

Operating it is pretty straightforward; you tell it what air pressure you want and it pumps until it gets there. The device is almost comically designed for a single purpose: It says it is not powerful enough to do many truck tires; it uses up to 15 amps, which just happens to be my cigarette lighter’s limit; and there are warnings not to use it for very long, lest it overheat.

It also came with an attractive-looking bag, quite obviously meant for tossing in the back of your car. It’s all about the size of a small football.

It has also, more importantly, freed me from the tyranny of gas station air pumps, which I hope to never use again. Some of you are probably thinking that I should’ve done this years ago, and you’re right. Those of you with an actual garage and a nice, proper air compressor will also still always have my envy.