Geez, I'm sorry but I feel that some of the advice above is shady at best, mainly because there aren't enough facts about what you have got, or enough facts given to you regarding the filtration cycle.
Firstly what sort of filter is it? An internal filter, or an external filter?
In most filters of either type there will be THREE types of filtration going on.
MECHANICAL:
This is normally acheived by the use of sponges, sometimes a series of sponges with reducing pore sizes. The 'stuff' floating around in your tank water literally gets caught in the sponge. The water flows through, the stuff doesn't.
BIOLOGICAL:
This is normally achived by the use of some ceramic type 'noodles', usually hollow cylinders, or sometimes plastic balls or corrugated tube.
These present a large surface area, and the beneficial bacterial of the nitrogen cycle will PREFER this media to live on & in. This bacteria is responsible for breaking down the ammonia produced by fish waste into nitrItes, and a second bacteria also housed here is then responsible for converting the nitrItes into nitrAtes.
Some of the smaller internal filters will not have these ceramics, and instead rely on the bacteria living on the sponges.
CHEMICAL:
Chemical filtration is achieved by use of activated carbon. This can be granuals in a pouch, or as an impregnated / coated sponge.
The carbon on the sponge absorbs the chemicals out of the water, but as such does not have a very long useful life. People generally give activated carbon a life of a couple of days to a week at most, (note, PEOPLE who USE it, not MANUFACTURERS).
As such many people will remove the carbon from their filters and use the space it leaves to add extra filtration of the other types, biological if it will fit, or if not then mechanical.
Also as Activated Carbon removes chemicals from the water, it will also remove any medication you add to the tank, and as such HAS to be removed before you start any form of medicating.
From the above you may think that you never need carbon, but thats not strictly true either. Many people will keep some carbon on hand for those occurances when you DO need to remove chemicals from the water, such as when you have completed a course of medication, or if you need to change medications.
So cleaning out your filter...
Charcoal;
Don't really bother with it, if you DO want to keep it in there all the time you are going to be looking at changing it at least weekly, at a push fortnightly, (thats not rinsing it through, but throwing it away and putting in a new replacement).
Biological media;
Generally you don't want to be 'washing' this at all. If it gets really gungy then you can give it a quick swish in a bucket of tank water, but nothing more, you don't want to be washign away all that lovely bacteria
Mechanical / Sponges;
As this is where the majority of the 'stuff' will get stuck these will need properly washing out. Again only do this in bucket of tank water, as tap water will kill off any bacteria that might have decided to make this home
Sponges should be replaced when either the flowrate through them is noticeably reduced, or when they start to breakdown (they can only take so much washing).
IF you do not have any 'biological media' (ie. ceramic stuff), then the largest amount of your bacteria is going to be living on these sponges. If this is the case you do NOT want to wash all your sponges at the same time, (presuming you have more than one), but should alternate which sponge you wash, and which one you leave settled in the filter. If you only have one sponge in the filter you will probably want to consider cutting it in half so that again you only have to wash 50% of it at a time.
