Water filters - do you HAVE to change them every month?

[annh]

DH says I have to ask the collective wisdom of MN what happens if we don't change our BRITA water filter every month, as advised. Do they stop functioning or are they OK (ish) until the water starts to taste a bit funny again?

There are carbon particles in your filter that help clean the water.

It is advisable to follow the manu's instrucs, but I sometimes get two months out of my filter - especially if you don't use it a lot.

If a family of 5 filter water 10 times a day - and you filter water only 5 times a day? See were i am going with this.

My DH reckons that over time bacteria will be growing in the filter and so its not a good idea to keep them going for too long. We do eek out an extra week on ours but we have very hard water and you can start to tell from the scum on the tea that its no longer working well enough.

we don't change ours monthly, more like every 2-3 months, I notice the taste changing then do it