When you have multiple spools of material in use, or do not print with a material, it is very important that you store them properly. If the material is stored incorrectly, it may affect its quality and usability.
More information can be found on this page.
Using the Material Station
With the Ultimaker S5 Pro Bundle and the Material Station, filament is automatically kept at the recommended humidity. The reliable humidity-controlled storage chamber maintains the loaded spools in optimum condition. More information about the Material Station can be read on this page.