Most of us know roughly when the milk goes off. Far fewer know when the smoke alarm in the hallway does. Yet the equipment that protects a home from fire and carbon monoxide wears out too, and unlike milk, it gives almost no sign that it has.
This guide covers the safety items that quietly carry a replace-by date, how long each typically lasts, and a simple way to make sure none of them lapses without you noticing.
Safety devices rely on parts that degrade with time. Smoke alarm sensors become less sensitive as dust and age take their toll. Carbon monoxide sensors are built to last a set number of years. Fire extinguishers can lose pressure. Sterile dressings stop being sterile, and medicines lose strength. None of this is visible from the outside, which is exactly why a date matters more than a glance.
Typical lifespans vary by model and country, so always check the manufacturer's label or manual first. As a general guide:
| Item | Typical lifespan | Where to find the date |
|---|---|---|
| Smoke alarm | Replace about every 10 years. The US National Fire Protection Association recommends replacing smoke alarms every 10 years. | Printed on the back or side of the alarm, often as a manufacture date or "replace by" date. |
| Carbon monoxide alarm | Commonly 5 to 10 years, depending on the model. Many newer alarms sound an end-of-life warning. | On the back of the alarm or in the manual. |
| Fire extinguisher | Varies by type. Many household extinguishers are designed to last around 10 years or more, but they need regular checks. | On the label or a service tag. Check the pressure gauge monthly if it has one. |
| Fire blanket | Varies. Follow the date or guidance on the pack. | On the container or instructions. |
| First-aid kit contents | Items such as sterile dressings, eye wash, antiseptic wipes and medicines all carry their own dates. | On each item's packaging. |
| Adrenaline auto-injectors and other emergency medicines | Have a printed expiry date, and replacements need planning ahead. | On the device and its packaging. |
Fire services in the UK and US give the same basic advice: test every smoke alarm once a month by pressing its test button, and replace the whole unit when it reaches the end of its life, usually after about 10 years. If your alarm uses replaceable batteries rather than a sealed long-life battery, change the battery at least once a year, or whenever it chirps.
If you move into a home and don't know how old the alarms are, look at the date on the back. If there isn't one, or it's older than 10 years, replacing them is cheap insurance.
Carbon monoxide has no colour, taste or smell, which is why an alarm is the only practical way to detect it at home. Fit one in any room with a fuel-burning appliance, such as a gas boiler, a wood burner or an open fire. In England, landlords have been required since October 2022 to fit carbon monoxide alarms in rooms with a fixed combustion appliance, other than gas cookers, and to repair or replace alarms when told they are faulty.
Carbon monoxide alarms usually last between 5 and 10 years. Many sound a distinctive end-of-life signal, but that's easy to confuse with a low battery. The safest approach is to note the replacement date the day you fit the alarm.
Keep a fire extinguisher and a fire blanket near the kitchen, where most house fires start, and make sure everyone knows where they are. Once a month, check that the extinguisher's pressure gauge, if it has one, is in the green zone, that the safety pin and seal are intact, and that there are no dents or signs of damage. The label or manual will tell you whether it needs servicing and when to replace it.
If you ever use an extinguisher, even briefly, replace or recharge it. A partly used extinguisher may not work the next time you need it.
A first-aid kit is really a small collection of products, each with its own date. Plasters lose their stick, sterile dressings pass their sterility date, and painkillers and antihistamines expire. Twice a year, open the kit, replace anything past its date, and restock anything that was used.
Pay particular attention to emergency medicines. If someone in your home has a prescribed adrenaline auto-injector, an inhaler or other rescue medication, keep an eye on the expiry date and order a replacement in good time. Your pharmacist or doctor can advise on the right timing.
Safety equipment doesn't announce when it has stopped doing its job, so the date is the only warning you'll get. An hour spent walking the house, recording dates and setting reminders is one of the most useful things you can do for your household's safety. Then test monthly and replace on time, and the equipment will be ready on the one day you need it.
This article is general guidance. Follow the manufacturer's instructions for your equipment and the advice of your local fire and rescue service.