3D filament normally are sold in weights of 0.5kg and 1kg. Based on the density, say 1 kg/m3 and the diameter of 1.75mm, the length for a 0.5kg and 1kg roll would be about 170m and 340m respectively. If we are not using the 3D printing as a form of business, chances are that we do not use up all the printer filament in one printing session. Very often, we need to store the filament and be used in another session. Especially, in countries with very high humidity, it is not a practice to simply leave the filament on the 3D printer even for a few days. It is always a good habit to remove the filament from the 3D-printer and store it properly when we are not going to use it overnight. 3D printer filament should be stored in a dry place. If the filament is stored properly in air-tight conditions, the filament quality can still be in a very good condition even after months of storage.