Usually manufacturers will set a date or litres used for changing over filters (whichever comes first). I would think there is some leeway with timing, but it’s always best to check with the manufacturer as a precaution.

Regarding bacteria, Brita say that the use of silver and the activated carbon used in their cartridges prevents growth of bacteria, and as long as the water in the jug stays in contact with the cartridge, it remains hygienically safe (see ).

I have used the Brita filters before and found they are OK for getting rid of chlorine and improving taste in water. However, I’ve recently started using the Waterman, which is a bit more expensive up front, but the filters last for up to 6 months. It filters to 0.1 micron and also re-mineralises the water, which is an effective way to increase the amount of essential nutrients in your diet. See for more info.

as you said u are 1 prson so that does factor in. i don’t know where u live but some places i’ve been to on vacation have had terrible drinking water and depending on how bad the tap water tastes before filtering might also be a factor. i think the last filter system i used was Britta and thought that when the filter was no longer filtering or working that there was some kind of aparatus that turned colors to show that the filter was longer any good? i believe thats the filter hooked onto your faucet, now if you are talking about the pitcher that may be different. in any case again i believe the fact there u are the only one who is using it chances are you haven’t over used it yet? i hope that helps.

Typically if manufacturer says “or” they mean “whichever comes first”. You may run into bacteria growth inside a cartridge.

“while not wasting any extra $$ throwing away filters”

Why would you use Brita cheap 2-stage filtration system, if there are much better out there? For instance, try Crystal Quest (link below), which is a 4-stage system, and filters last at least 6 months? It is a Consumer Digest magazine “Best Buy” for 2006.