I trudged through the snow to buy a bottle of window washer fluid, filled the container on the Honda, and then noticed I had three other opened bottles in the garage. This is known as wasting your winter car prep time.

Assuming you live in the Snow Belt — and this means you, Rochester, Detroit, Kennebunkport and Medicine Hat — not getting your car ready for winter is like going to the beach without SPF30 (at least). Here are some key things not to forget. And it’s OK to do them now, even though winter has already arrived with a vengeance.

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Getting ready. It’s best to replace your antifreeze if it’s been in there a while, but at the very least, check its effectiveness with a hydrometer. These are $10 on Amazon or from the local hardware store. Have your mechanic make sure your battery and the charging system it depends on are up to snuff, and both the heater and defroster are working. Give the brakes a good looking after, too, and make sure the headlights are aimed properly (clean the lenses while you’re at it). Things to carry: a flashlight, scrapers and a snow brush, jumper cables, washer fluid, flares.

Subaru in snowAll Subarus have four driven wheels, but don't assume that alone will get you through winter's blasts. (Photo: Jim Motavalli)

Talking tires. Those winter tires in your garage, mounted on a spare set of rims? Time to put them on. What, you don’t have winter tires? You think that “all-season” tires will see you through? Think again; they’re OK in light dustings, but not blizzards. I talked with Bridgestone about this at the Detroit Auto Show, and Pep Boys will tell you, “If you drive regularly in cold, icy and/or snowy conditions during the winter months, winter tires are a smart investment.” The initial outlay may be a bit stiff, but you’ll be good to go for years.

Other tire tips: check your inflation, and set it to the recommendation in the owner’s manual. Tires tend to lose air over the winter. Confirm your tread depth is sufficient. And it helps to have four matching tires — the worst thing you can do is mix radials with old bias-plies you may have found cheap.

SUV overconfidence. Americans tend to think that four-wheel drive will get them through anything, and that SUVs never get stuck. Both are fallacies. I’ve seen a lot of SUVs in snowbanks, and the state police confirm that impression. Having four driven wheels does nothing to maintain grip on ice — the winter tires mentioned above are much more important.

SUV stuck in snow.Yes, SUVs do get stuck in the snow. (Photo: Jeff Lautenberger/Flick)

Exhausted. Be very, very careful about warming up and idling your car. The disturbing proliferation of remote starters means more people are doing this. Yes, you get a warm vehicle, but you also waste a lot of gas in the process. It’s an old wives’ tale that the car benefits from a warm-up. Don’t leave the car running in the garage. And I just read about a family that was poisoned by carbon monoxide while sitting in a warming car because the exhaust pipe was blocked by snow.

Driving in snow. Stay home! But if you do go out, drive slow and steady — no lead feet, with lots of distance between other cars. And if you do lose control, turn in the direction of the skid (in other words, the direction the back end is moving). Stopping distances can be doubled by snow or ice, and don’t jam on the brakes if you can help it as that encourages skidding. Get up hills on inertia — hitting the gas on a snowy hill will spin the wheels. Whatever you do, don’t stop on a hill; it can be near impossible to gain momentum again. Don’t use your cruise control in snow or ice. On automatic cars, leave the parking brake off when parked. If you do get stranded, stay with the vehicle.

winter sliding.When the weather stinks, stay home and slide down your driveway. (Photo: Zlatko Unger/Flickr)

Odds and ends. Keeping the gas tank as full as possible means you won’t run out in the middle of a blizzard, or have starting problems because of moisture forming in the gas lines … Switch to “winter weight” oil at the next change interval … Get that tune-up now, because the cold worsens related problems such as hard starting, rough idling and pinging.

The bottom line: Be prepared, and be sensible! Here are some more tips on video:

Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.