How long do you have filament sitting “in the open”? I mostly print with a single filament roll at a time, and just leave it on the printer. A 1kg roll lasts me several weeks. For long time storage I keep it in an air tight box with disiccant pouches.
But how long can I let it sit before I should start storing it with disiccant and/or drying the filament before use?
If the filament comes in a resealable bag, I simply store the spool in there with some desiccant. For everything else, I use resealable 2-gallon bags with desiccant. My basement humidity is very stable around 30%, and I don’t really have issues. I’ve never dried filament before printing. That’s going on 6 years.