You know, the kind on the faucet, or built into the pitcher? The manufacturer says every 2 months, but I’m assuming that’s to make me buy more filters…
Should I just wait until I can taste the contaminants in the water again? We have chloramine treated very hard water around here.
I think how long a filter lasts largely depends on the incoming water. We have a whole house filter. We use the charcoal taste and odor cartridges. Sometimes it is a month or more before before we notice a pressure drop and sometimes less than a week. That usually is when the water table is high and we get a lot of iron oxide. If you are still getting good water, I would let it go.
Low pressure, the cartridge has filtered out enough material that it has become clogged and severely restricts flow through it.
Breakthrough, the cartridge has reached capacity and the material/smell can now travel through the filter.
6 months go by, the filter can begin to physically break down or bacteria could begin to reach dangerous levels. A filter could easily last longer but best health practices dictate 6 months maximum or as recommended by the manufacturer.
Of course as you’ve pointed out the manufactures recommendations time might not reflect the limitations of the filter but their sales goals.