The cartridges have a small desiccant pack within the cartridge, but most spools I had to take out of the cartridge because of winding and binding issues, so they are more exposed to the environment.
So it is best if complete cartridges or separate spools stay sealed with a desiccant as much as possible.
Any complete cartridges or separate spools that are not in current use, I put in a small kitchen trash bag with a desiccant pack.
Make sure to get most air out of the bag and close the bag so it is sealed.
Even new complete Cartridges should be stored and sealed in a bag with a larger additional desiccant. (I had filament braking issues also on complete cartridges). The desiccant in the cartridge is tiny and the cartridge itself is not very sealed by itself. And if you have used the cartridge, you have a bunch of filament out of the cartridge that you want to protect from moisture absorption.
Make sure to install the locking screw into the cartridge before taking out of the CubeX and remove the locking screw again once installed back into the CubeX.
With open Spools, after a print, I take the spool of the holder and stick it into a plastic bag with a pouch of desiccant. There is still filament exposed between the spool and print head, so if I know I won't print with that spool for awhile, it is best to pull the whole filament out of the printer like you would do if you change cartridges, so you can keep the whole filament with spool or cartridge sealed up.
I had a spool where the filament had become brittle, but after storing in a bag with a few desiccant pouches it seemed less brittle and was useable again.
Here is where I got the desiccant pouches. The 10 gm are good size pouches.
Note: The moisture absorption issue applies mainly to PLA, but I treat PLA and ABS the same and keep them both sealed as much as possible.
Also, when removing the spool from a cartridge, make sure to write onto the spool, which cartridge it belongs to, so you don't get them mixed up if you have multiple cartridges of same color etc..
Also, tape the end of the filament on the spool to the side of the spool, so it keeps the winding tight when the spool is bagged.