Sawyer has working filters that have been in continuous use for over six years and had filters which have filtered hundreds of thousands of gallons of water. Sawyer’s fibers are so robust, they can be back washed and reused perpetually.
When backwashing, even the stubborn dirt can be forced off the fibers.
Sawyer’s robust fibers will not “wear out” over time.
Sawyer fibers will not break or become damaged if dropped. Only breaking the sealed casing and “playing” with fibers or freezing the cartridge after it is wet could damage the fibers.