When I first got into 3D printing, I treated filament like a static material. PLA was PLA, PETG was PETG, and once I had a profile that mostly worked, I a**umed the rest was just pressing print and waiting. Winter made that belief fall apart in a hurry. The same spool that behaved nicely a month earlier could suddenly string more, crackle a little, or refuse to stick to the bed the way I expected.