When to Replace Everything in Your Home
A room-by-room checklist of how often to replace the everyday things you own — and the health reason behind each one.
Most of us have no idea when we last replaced the water filter, the kitchen sponge, or our pillows. The information exists — it's just scattered across dental associations, manufacturer fine print, and public-health guidance. Nobody carries it around in their head.
So we put it in one place. Below is a practical home-maintenance checklist: what to replace, how often, and why it matters. Intervals are general guidance — your mileage varies with use, water quality, allergies, and pets — but they're a sensible default for a healthier home.
Prefer to have this remembered for you? Sundry is a free iPhone app that tracks all of this and reminds you before anything is due.
Quick-reference table
| Item | Replace every | Why it matters |
|---|---|---|
| Manual toothbrush | 3 months | Frayed bristles clean poorly and harbor more bacteria |
| Electric toothbrush head | 3 months | Worn bristles lose effectiveness |
| Kitchen sponge | 1–2 weeks | One of the highest bacterial loads in the home |
| Contact lens case | 3 months | Biofilm builds up and can cause eye infections |
| Razor blade / cartridge | 5–10 shaves | Dull blades nick skin and raise irritation and infection risk |
| Loofah / shower pouf | 3–4 weeks (natural), 2 months (plastic) | Traps dead skin and bacteria in a damp environment |
| Mascara / liquid eyeliner | 3 months | Bacteria grow in the wet tube near your eyes |
| Pillows | 1–2 years | Accumulate dust mites, oils, and allergens; lose support |
| Mattress | 7–10 years | Loses support; accumulates allergens |
| Bath towels | 1–3 years | Stop absorbing and hold bacteria when they can't dry fully |
| HVAC / furnace filter | 1–3 months | Clogged filters worsen indoor air quality and strain the system |
| Water filter (pitcher) | ~2 months / 40 gallons | Spent filters stop working and can harbor bacteria |
| Refrigerator water filter | 6 months | Same — flow drops and filtration fails |
| Smoke & CO detector batteries | 1 year | Dead batteries mean no protection |
| Smoke / CO detector unit | 10 yrs (smoke) / 5–7 yrs (CO) | Sensors degrade and stop detecting reliably |
Bathroom
- Toothbrush (and electric brush heads) — every 3 months. Bristles fray and lose cleaning effectiveness, and worn brushes harbor more bacteria. Swap sooner if the bristles splay before three months, or after you've been sick.
- Tongue scraper — every 3 months. Same logic as a toothbrush: it lives in a wet environment and wears down.
- Contact lens case — every 3 months. This is the one most people never think about. Biofilm and bacteria build up inside the case and are a genuine route to eye infections — replacing the case matters as much as the solution you put in it.
- Razor blade / cartridge — every 5–10 shaves (roughly 1–2 weeks of regular use). Dull blades tug at skin and cause nicks, which raises irritation and infection risk. A sharp blade is safer, not just closer.
- Loofah / shower pouf — every 3–4 weeks (natural) or 2 months (plastic mesh). It sits damp in the shower trapping dead skin — a near-perfect environment for bacteria and mold.
- Mascara & liquid eyeliner — every 3 months. Wet tubes near your eyes grow bacteria fast. This is a health interval, not a vanity one.
- Bath towels — every 1–3 years. Replace when they stop absorbing; a towel that can't dry between uses holds bacteria.
Kitchen
- Kitchen sponge — every 1–2 weeks. Sponges carry one of the highest bacterial loads in the entire home. Microwaving a damp sponge daily helps, but doesn't replace replacing it. This is the single most-overdue item in most kitchens.
- Dish cloths / towels — wash every few days, replace when worn.
- Water filter (pitcher) — every ~2 months, or 40 gallons. A spent filter stops filtering and can become a home for bacteria. Most people run theirs far too long.
- Refrigerator water / ice filter — every 6 months. Flow rate dropping is your cue if you've lost track.
Bedroom
- Pillows — every 1–2 years. They accumulate dust mites, oils, and allergens, and lose the support that keeps your neck happy. The fold test: fold it in half — if it doesn't spring back, it's done.
- Mattress — every 7–10 years. Beyond comfort, older mattresses accumulate allergens. Rotate it in the meantime to extend its life.
Whole home: air, water & safety
- HVAC / furnace filter — every 1–3 months. This is the highest-impact item on the list for indoor air quality. Clogged filters worsen the air you breathe every day and make your system work harder (raising energy bills). Homes with pets or allergies should lean toward monthly.
- Smoke & carbon-monoxide detectors — test monthly, replace batteries yearly, replace the unit every 10 years (smoke) or 5–7 years (CO). The sensors themselves degrade — a detector that still beeps when tested can still be too old to detect reliably. Check the manufacture date printed on the back.
- Fire extinguisher — check the pressure gauge monthly, replace or service roughly every 10–12 years.
The hard part isn't the list — it's remembering
You've just read the intervals. The problem is that none of these items announce themselves. Your sponge doesn't beep. Your water filter doesn't flash. Prospective memory — remembering to do something at the right future moment — is one of the most fragile things our brains do, and "replace the HVAC filter in six weeks" is exactly the kind of intention that evaporates.
That's the whole reason we built Sundry.
Let Sundry remember for you
Sundry is a free iPhone app that comes preloaded with everything on this checklist. Tap the items you own, tell it when you last replaced each one, and it reminds you before each is due — with the health reason attached, so you always know why. No ads, no tracking; reminders stay on your device.
Made by Toolwright — small tools, carefully made.
Frequently asked questions
How often should you replace a kitchen sponge?
Replace a kitchen sponge every 1–2 weeks. Sponges carry one of the highest bacterial loads in the home; microwaving a damp sponge daily slows growth but doesn't replace regular replacement.
How often should you replace a toothbrush?
Replace a manual toothbrush or electric brush head every 3 months, or sooner if the bristles fray. Worn bristles clean less effectively and harbor more bacteria.
How often should you replace an HVAC filter?
Replace a standard HVAC or furnace filter every 1–3 months. Homes with pets, allergies, or heavy use should replace monthly; clogged filters worsen indoor air quality and strain the system.
How often should you replace a contact lens case?
Replace your contact lens case every 3 months. Biofilm and bacteria build up inside the case over time and can lead to eye infections, so replacing the case matters as much as replacing the solution.
How often should you replace pillows?
Replace pillows every 1–2 years. They accumulate dust mites, oils, and allergens and gradually lose support. If a folded pillow doesn't spring back, it's time.
How often should you replace a water filter?
Replace a pitcher water filter about every 2 months (or 40 gallons), and a refrigerator water filter every 6 months. A spent filter stops filtering effectively.
Is there an app that reminds you when to replace household items?
Yes, Sundry is a free iPhone app that comes preloaded with health-backed replacement timing for dozens of household items and reminds you before each is due.