I have a sponge, bio cubes, and crushed coral right now. I do not have pre filter
I would give the sponge a light squeeze in some used aquarium water every few weeks. I would only clean the cubes if they look dirty or clogged, then only a quick dip in the water. The crushed coral shouldn't need anything.
Don't replace the sponge unless it starts to disintegrate. The cubes should last for years, again if they aren't disintegrating don't replace them. I would change the coral every 6 months or so.
If you decide to change any media try to only replace half of it at a time so you don't throw too many bacteria away. If your sponge is one piece cut it in half to replace half at a time.