Each additive manufacturing vendor will have their own instructions, however, an example can help guide you. Let’s take the HP MultiJet Fusion system, which uses powder material for building objects. This system was based on 2D printing technology. Therefore, like a 2D printer, there are three different print heads and there’s a capping station. When the print heads are idle or the machine is idle, it’s sitting inside of a capping station that is sealed from any air getting into the line.
Usually this 3D printer can be idle for a month or two. But when you work with it again, you should cycle it before a print. All 3D printers want to run. A week or two of idle time should not affect the printer. A maintenance cycle would ensure that material moves through the lines. For long periods of shut down, the printer should be put in shut down mode.
Material canisters are completely sealed when new, so no moisture can get in. As long as the canisters are capped off after use, then moisture should not penetrate the canister itself.