course blue/fine blue; should never need changing unless you allow then to become really clogged. if you rinse them in tank water every water change they should last for year and years.
green (nitrate); every 6 weeks. IMHO a waste of money, replace with a fine blue sponge.
Black (carbon); every 6 weeks. again not needed unless you want to absorb something specific, like after a medication course. replace with a course blue.
white (floss); you may get a couple of washes before this starts to disintegrated, only replace then unless you are made of cash and can afford to replace every water change.
on a side note,
the rekord 96 pump is only a 280, you could upgrade to a 400 or 600, making the filter more efficient.
HTH