Filter cartridge Change

So I'm about to do a water change on my 5 gallon tank and I'm wondering when I should change the filter cartridge. I have read that the cartridge that is in there now has the good bacteria in it, and starting over with a new one will be like taking everything out of the tank and not only cleaning all of the bad bacteria out of the gravel but also the good bacteria. What should I do because I have had this one filter cartridge in there for a while?

personly i never change filter cartriges/sponges unless they are falling apart, why get rid of the bacteria you have worked so hard to get lol im not saying never change it but for the most part a good swill/rinse in the tank water you take out on a water change will do the trick.

+1 for Phil.

Just swish the media in old tank water, and stick it back in the filter until it falls apart. The only reason you really need the new one, is for the activated carbon to take meds out. The carbon only lasts about 2 weeks.

Wow! I wish I had read this yesterday before I hit Petsmart LOL. I just bought a twelvepack of replacement cartridges.
So, since I have never used meds or any other type of water additive, I shouldn't worry about replacing filter cartridges until they are in really bad shape? And in fact I am better off just rinsing the cartridges periodically?
I know nothing about filters. I was going by the company recommendation of replacing the cartridges every couple weeks as the little plastic red thing says to. I only got filters for my bettas' tanks cause it just seems that they must be good. Plus LG loves playing in his filter current LOL.

No need to put new ones in, unless they're falling apart.
Next time, if you don't need to take meds out, just get some poly-fiber at Walmart or something, and use that.

Well it'll be a while Dk. I'm set for cartridges for the next couple years, I think LOL.