The best thing in life is to be able to breathe... especially inhaling clean air. By getting an air purifier, clean air is obtainable easily for you and your family without having to live in the jungles. If you already have one, then you might want to know how to prolong its life.
New filter means better filtration, thus provides cleaner air.
Clean filter means better performance, thus air purifier lasts longer.
Less material means less resources wastage, thus more nature-friendly.
Replaceable filter helps to save more in the long run, thus more cost-friendly.
When it's over the recommended usage period stated on the packaging.
When there's an indication on the LED or digital display (only on selected models).
When it emits musty and unpleasant odour when switched on.
When the filter is extremely soiled with dust and dirt.