Fire Blanket
A fire blanket lasts around 7 years if it stays sealed and undamaged — but it is single-use, so any blanket that has smothered a fire is thrown away afterwards.
What actually ages
Glass-fibre fire blankets do not rot, but they do not last forever either. The fabric itself is stable for years; what ages is everything around it — the plastic pouch or quick-release case grows brittle in sunlight, damp creeps into a garage-stored blanket, and the pull-tabs stiffen. Most manufacturers to BS EN 1869 give a service life of around seven years for an unused, undamaged blanket, after which they recommend replacement.
Check it without unpacking
You do not need to open it. Check that the case is intact and the two pull-tapes hang free, that the blanket has never been folded back damp, and that any printed date has not passed. A cracked case, water stains or a missing tab are all reasons to replace it rather than gamble in an emergency.
One fire, then gone
A fire blanket is single-use. Once it has smothered a pan fire or wrapped a person, the coating and fibres have been heat-stressed and it is thrown away — never refolded and put back on the wall. Keep it where a fire is most likely: mounted beside the kitchen door, not behind the hob where you cannot reach it through the flames.