Because the filtration lifetime of our membrane microfilters, membrane ultrafilters, and carbon filters vary based on configuration within specific products, we recommend reviewing the specific filtration lifetime for the filter and product you are using when determining the right time to replace your filter.
However, in general, the membrane microfilter will stop allowing water to pull through once it's reached the end of its lifetime. We recommend changing your carbon filter (and activated carbon + ion exchange filter) according to the included directions, but best practice is before you notice a change in taste or smell of your water.