How often should you change your oil?

For decades the rule was simple: change your oil every 3,000 miles. It was easy to remember, and for a long time it was roughly right. Today it’s largely outdated. Modern engines are built to tighter tolerances, and modern oils — especially synthetics — last far longer than the oils that rule was written for. Sticking rigidly to 3,000 miles usually means changing your oil, and paying for it, two or three times more often than your car actually needs.

The number that replaced it is bigger and less tidy. Most modern vehicles are designed to go 5,000 to 7,500 miles between changes on conventional oil, and often much further on full synthetic. But the honest answer to “how often should I change my oil?” isn’t a universal figure at all — it’s whatever your owner’s manual specifies for your exact make, model, and oil type. That manual is the single most reliable source, and it beats any rule of thumb, including this guide.

The right interval depends heavily on what’s in the engine. As a common rule of thumb — and always deferring to the owner’s manual written for your specific car:

• Conventional oil — roughly every 5,000 to 7,500 miles.
• Synthetic blend — often around 7,500 miles.
• Full synthetic — commonly 7,500 to 15,000 miles, depending on the manufacturer.

The spread is wide because oil chemistry has improved so much. Full synthetic resists breaking down under heat far better than conventional, which is why it can safely go so much longer. Many newer cars also have an oil-life monitor that estimates the interval from how you actually drive — worth trusting, though it doesn’t replace the manual.

One more nuance: severe conditions — lots of short trips, stop-and-go traffic, towing, extreme heat or cold, or dusty roads — shorten every one of these numbers. If that describes your driving, lean toward the lower end of the range for your oil type rather than the top.

Mileage isn’t the whole story. Oil degrades with time, not just distance, because it oxidizes and absorbs moisture and combustion byproducts even when the car mostly sits. That’s why manufacturers pair a mileage figure with a time limit — you’ll see it written as something like “7,500 miles or 6 months, whichever comes first.”

For a low-mileage driver, the time limit is usually the one that matters. If you only put a few thousand miles on the car a year, you’ll hit the 6-month mark — or, per some manuals, 12 months — long before the mileage number, and the oil still needs changing. Plenty of well-kept, rarely-driven cars end up with degraded oil simply because the owner watched the odometer and never the calendar. The takeaway: whichever limit you’ll reach first is your real interval, and for many drivers that’s the clock, not the miles. A tracker that counts months is exactly what those drivers are missing.

Skip oil changes long enough and the damage moves from your wallet to your engine. As oil ages it thickens into sludge and loses its ability to lubricate. Without a proper film between them, metal parts grind against metal, generating heat and wear. Old oil also stops carrying heat away, so the engine runs hotter — and a hot, poorly lubricated engine can warp parts, blow a head gasket, or in the worst case seize entirely. A seized engine usually can’t be repaired; it has to be replaced, which can cost more than the car is worth.

Long before that point, a neglected engine loses efficiency and burns more fuel fighting through the grime, and skipping the manufacturer’s schedule can void your warranty. It’s the classic false economy: the oil change you put off to save a little now is the very thing protecting the most expensive component in the vehicle. The part isn’t hard or costly — remembering it on time is the whole game.

Oil is the most famous item on a car’s schedule, but it’s far from the only one running on an interval you have to track. A few common rules of thumb, all subject to your manual:

• Tire rotation — roughly every 5,000 to 8,000 miles, often paired with an oil change.
• Engine air filter — commonly every 15,000 to 30,000 miles.
• Cabin air filter — often every 15,000 to 25,000 miles, or about once a year.
• Wiper blades — typically every 6 to 12 months.

Each of these has a different clock, and none of them lights up a dashboard warning when it’s due. That’s what makes car maintenance so easy to let slide: the intervals are long, they’re all different, and the car rarely reminds you until something has already gone wrong. Bundling the ones that share a timing — like rotating your tires at the oil change — helps, but the rest still need something keeping count.

An oil change takes an afternoon or a quick shop visit. Remembering that it’s been five months, or that you’re closing in on 7,000 miles, is the part that trips people up — the car doesn’t nag you, and one skipped interval blurs into the next.

That’s the gap Dutiful is built to fill. Add “oil change” once — it’s in the app’s 120+ preset library with a sensible default interval — set how often it should happen, and tap “Did it!” each time it’s done. Dutiful keeps the clock and reminds you, gently and in the morning, when the next one’s due, sorting your car jobs by what’s most overdue. Tire rotations, wiper blades, and registration renewals can all live right beside it.

Because these tasks are too irregular for a calendar and too rare for a habit, they need a tracker built around one question: “when did I last do this?” The guide on how to remember recurring tasks covers that whole idea, and it works just as well for the home maintenance side of your life.