How Often Should You Replace It? A Checklist for Home, Car, Health and Pets

The hardest part of most maintenance isn’t doing it. It’s remembering when you last did. This page lists how often common things need checking or replacing, each with the organization or manufacturer the number comes from.

Your manual comes first. These are general guidelines. Your appliance, car or filter manual, the label on the product, your dentist or your vet always win where they differ.

Home safety

What	How often	Notes	Source
Smoke alarm: test	Every month	Press the test button, including on sealed 10-year alarms	NFPA, US Fire Administration
Smoke alarm: battery	At least once a year	Also the backup battery in hardwired alarms. Sealed 10-year alarms don’t need one. Replace right away if it chirps	NFPA
Smoke alarm: whole unit	Every 10 years	From the manufacture date on the back, or sooner if it fails the test	NFPA
Carbon monoxide alarm: test	Every month		NFPA
Carbon monoxide alarm: unit	Typically every 7–10 years	Follow the manufacturer’s date or the end-of-life signal	NFPA, Kidde
Fire extinguisher (home)	Check monthly	Gauge in the green, no dents or leaks. Kidde: disposable units last 12 years from manufacture	Kidde
Dryer lint filter	Every load		NFPA
Dryer vent / duct	At least once a year	More often if clothes take longer to dry	NFPA, US Fire Administration
Chimney and fireplace inspection	Once a year	Even if you rarely use it	CSIA (NFPA 211)

Filters, heating and water

What	How often	Notes	Source
Furnace / HVAC filter	Check monthly, change at least every 3 months	Sooner when it looks dirty, especially in heavy-use winter and summer months	ENERGY STAR
HVAC tune-up by a pro	Twice a year	Cooling in spring, heating in fall	ENERGY STAR
Refrigerator water filter	About every 6 months	Or the filter’s gallon rating, whichever comes first; follow the filter light	Whirlpool, Samsung
Pitcher filter (Brita Standard, PUR)	About every 2 months (40 gallons)	Brita Elite: about 6 months (120 gallons). Sooner with hard water	Brita, PUR
Under-sink filter	As rated by the maker, often up to 6 months	Each cartridge has a time and a gallon limit, whichever comes first	CDC, NSF
Range-hood grease filter	Clean monthly to every 6 months	Depends on how much you cook; charcoal filters are replaced, not washed	GE Appliances, Broan-NuTone
Water heater (tank) flush	About once a year	Every 6 months with hard water; your manual decides	Rheem
Septic tank	Inspect about every 3 years, pump every 3–5 years	Depends on tank size, household and water use	US EPA
Gutters	At least twice a year	Spring and fall, more often under trees	UGA Extension

Car

What	How often	Notes	Source
Oil change	Per your owner’s manual or oil-life monitor	”Every 3,000 miles” is outdated for most modern cars. Short trips, towing and heat mean shorter intervals	AAA
Tire pressure	Every month, tires cold	Use the pressure on the door label, not the tire. Check the spare too	NHTSA
Tire rotation	Commonly every 5,000–8,000 miles	If your manufacturer recommends it	NHTSA
Wiper blades	Every 6–12 months	Sooner after harsh sun or a freezing winter, or when they streak	AAA
Car battery	Usually lasts 3–5 years	Have it tested as it ages; heat and short trips shorten it	AAA
Cabin air filter	Per your manual, roughly 15,000–30,000 miles	Sooner with smoke or dust	AAA
MOT (UK)	Every year from the third year	Northern Ireland: from the fourth year	GOV.UK

Health and home life

What	How often	Notes	Source
Toothbrush or brush head	Every 3–4 months	Sooner if the bristles are frayed. NHS: every 2–3 months	ADA, NHS
Dental check-up	As your dentist recommends	There’s no single rule; it depends on your risk. UK: from every 3 months to every 2 years	ADA, NHS
Contact lens case	Every 3 months	Rinse and air-dry it after every use	FDA, CDC
Bed sheets	Wash weekly, at least every 2 weeks	More often if pets sleep in the bed or you have allergies	Sleep Foundation
Pillow	Every 1–2 years	Depends on the fill	Sleep Foundation
Mattress	Every 6–8 years	Sooner if it sags or allergies get worse	Sleep Foundation

Pets

What	How often	Notes	Source
Heartworm prevention	All 12 months, plus a yearly test	Most preventives are monthly; follow the label	American Heartworm Society
Flea and tick prevention	Year-round, at the label’s interval	Often every 30 days, some products every 2–3 months. Never use dog products on cats	CAPC
Vet check-up	At least once a year	Seniors every 6 months (dogs over 7, cats over 10)	AAHA, AVMA

Remembering the last time

Knowing the interval only helps if you know when you last did it. That’s what we built SinceNow for: add a task once, tap reset when you do it, and it shows how long it’s been, with a note each time (“16x25x1 filter, $11”, “5W-30, 48,200 km”). It’s free on iPhone, Android and the web, and many of the items above are ready-made templates.

Spotted an interval that changed? Write to [email protected]. We check the sources every month.