How will adding more media to canister help the tanks?

[Milky]

I have one empty media basket in each of my fluvals
and the tanks are fully cycled with very clear water. Im just
wondering if i get some more media for the empty baskets
how will this help the tank. Or is this just a case of "if its not broken dont fix it situations"...

[Hound]

I'd say you should go ahead and leave the baskets empty for the time being. When it comes time to change your bio media you can make use of the empty baskets to give time for bacteria to grow on the new media.

[OrionGirl]

Alternating in fresh bio-media is one good benefit--another is that you will have the space to add chemical filtration if needed--ie, carbon to remove medication, ect. There's no need to use all the baskets if the tank is stable, and having some cushion room is a good thing.