How long do pans last? Or knives, or cutting boards? The milk and eggs in your fridge aren't the only kitchen items with expiration dates. Many are surprisingly perishable, and have lifespans that eventually run their course. Push past their expiration dates, and these items may lose their full functionality ... and even affect the taste of your food.

So, just in case you've been hanging onto certain utensils for longer than you should, check out this list of the useful life of certain common items—and how to extend it through a little kitchen maintenance.

How long do pans last?

Lifespan: Many years for cast iron, three to five for nonstick pans

A cast-iron pan will last for generations, but its nonstick cousin needs replacing after just a few years. The reason? "The coating starts to flake off and may work its way into your food—and that's not safe," notes Jennifer Snyder, a certified professional organizer at Neat as a Pin.

Make it last: It's sort of cool to see water sizzle on a hot pan, but don't be tempted to try it out. "A burning frying pan will warp if you toss it in a full sink—this shocks the metal," explains Jamie Novak, a professional organizer and author of "Keep This Toss That." Always use wooden, plastic, or silicone utensils on a nonstick skillet, because metal can scratch. And all pans last longer if you wash them by hand (no wire brushes!) and slip paper towels in between each to protect the coating.

How long do knives last?

Lifespan: A year or two

Sure, you can sharpen and resharpen your knives, but the ones you use daily take a serious beating. "Paring knives are some of the sharpest in the drawer, but when the blade wears down, they're not effective and even dangerous," warns Novak.

Make it last: Knives get bumped around in drawers and the dishwasher, so store them in a knife block or on a magnetic wall strip and wash them by hand. And when you are finally ready to bid a blade adieu, "Homeowners should check with their local municipality, as some have recycling centers that can melt down the blades," Novak explains.

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How long do dish towels last?

Lifespan: About a year

Dish towels are kitchen workhorses, but once they look worn and ratty, move them to your rag bag. Pro tip: Stock up on them when they go on sale, so you have a drawer of at least 10 or 15 to get you through the week.

Make it last: "If you wash them regularly in hot water and diluted bleach, you'll extend their usefulness," points out Sarah Hollenbeck of Offers.com. And dry towels thoroughly to prevent mildew—and the odor that comes with it—from setting in.

How long do cutting boards last?

Lifespan: Several years

Has your board been gouged and nicked? Toss it right away, says Novak, as scratches are difficult to clean and can breed bacteria. But if the surface is still smooth, whether plastic, laminate, or wood, you can keep it for four or five years.

Make it last: "Wooden boards can actually be sanded down and used longer, though you'll lose the original finish," says Hollenbeck. Don't toss wood in the dishwasher (the heat can enlarge cracks). Air dry all boards, and consider a bit of mineral oil on wood to combat dryness.

How long do toasters last?

Lifespan: Five years

This little appliance needs TLC every time you use it, or it won't live to the end of the warranty.

Make it last: Clean up spills and burnt bits so they don't drip onto the heating elements and ignite your bagel (or the appliance itself).

How long does Tupperware last?

Lifespan: A year or two for sturdy Tupperware; mere months for deli or takeout containers

Stains aren't a big deal, but when your plastic containers start to get cloudy, pitted, or bent out of shape, recycle them—fast. Bacteria can settle into grooves, which may contaminate food.

Make it last: The microwave does a number on these, so reheat food in glass or ceramic dishes only. And while you may not enjoy washing anything by hand, the dishwasher's heat can damage certain materials. If you must use the machine, load containers in the top rack, where the temperature is lower.

The article originally appeared on Realtor.com.