PLA is fairly moisture sensitive I find, in the UK where in house humidity is regularly 65-70% a roll of PLA left out in the fresh air degrades quite quickly for me. What this causes for me in printing is greater ooze on the nozzle. The water in the filament boils off and pushes the filament out of the nozzle even though I’ve got retraction set quite high.
My quick go-to fix is to store the filament in an Ikea plastic lidded box when not being used with some of those little silica gel pouches you get in pretty much every roll of filament. If I’ve got a spool that’s been out a lot (usually an end roll) I put it on a towel on the radiator when the heating comes on to gently warm it and drive off the moisture.
