Most repairs don’t pop up out of the blue because most major purchases, like these, have expected lifespans. Knowing them—plus, how to extend them—can help us budget better and preserve that emergency fund for when we really need it most.

Laptops

“A home-class PC or Mac will last about three or four years,” says David Hunt, technical director at computer repair company, Gurus2go. “Business-class laptops, which can cost a couple hundred extra, are more robust and can last four to six years.”

To stretch out that lifespan, Hunt recommends always transporting the laptop in a protective case, and avoiding resting it on soft surfaces, like clothes or bedding. “A laptop can run extra hot if you block the vents for the cooling fan. The risk is you’ll overheat the capacitors on the motherboard and fry it.”

Cell Phones

The average person keeps their phone for about 14 months, says Dave Rivas of PHONEDOCTORS. “But that’s because they’re choosing to upgrade to newer models. You should be able to keep one about three years. After that, manufacturers usually stop supporting their phones, so they become harder to keep using.”

Cracked screens represent nearly three-quarters of repair requests, Rivas says—so he recommends using a protective case and tempered glass screen protector, rather than plastic film (which protects against scratches, not impact). Apple also offers an extended warranty AppleCare+ program for about $129 per two-year period, which covers accidental damage (but not theft or damage from “reckless” conduct).

Cars

“You can reasonably expect a new car to last at least 100,000 miles and 10 years without major repairs,” says Matt DeLorenzo, news managing editor at Kelley Blue Book.

Regular oil changes are the biggest single factor in longevity. “If you don’t check your oil and run out, the engine life will be very short,” DeLorenzo says. “If you merely skip oil changes and keep it topped off, dirt and other contaminants will build up in the engine, eventually causing premature wear.”

If you’ll keep your car a while, DeLorenzo says it’s worth considering extended warranties, as most basic policies only cover the first three years. “The best ones take care of catastrophic events, like an engine or transmission failure, with minimal deductibles,” he says. “Dealers are good sources, but you also want to check associations like USAA and other insurance providers.”

Mattresses

Though a mattress can technically last more than a decade, the non-profit Better Sleep Council (which, it’s worth noting, is supported by the mattress industry) recommends replacing them every seven years for optimal comfort and support. In the meantime, rotating your mattress twice a year can prevent sagging.

Roofs

Weather is often the biggest factor in how long a roof lasts, but you can expect different lifespans according to material, too. Roofs made of slate, copper or clay/concrete last the longest—typically more than 50 years—while ones made of wood or asphalt shingles last 30 and 20 years, respectively. Keeping your gutters clean is a good way to extend the lifespan by preventing water damage.

TVs

LCD (liquid crystal display) televisions are the most common type sold today, though OLED (organic light emitting diode) can be found in some higher-end sets. Both types last about 100,000 hours before losing half the brightness. So, even if you watch four hours of TV every day, your TV will last decades before getting unusably dark.

Other Major Appliances

According to Sears, washing machines, dryers, refrigerators and dishwashers can last between 10 and 13 years. Gas ranges typically last for 15, while stovetops can keep going for 15 to 18 years. Microwaves generally last for nine to 10 years.

Those lifespans can vary with use, though: Dishwashers actually benefit from regular use, because it keeps seals, hoses and gaskets from dry-rotting. To extend the life of a refrigerator, clean the condenser coils (located on the back or bottom of the fridge) once or twice a year.