The quality of the filament is frequently mentioned either as the source of an issue but also as the solution to a problem.
I know that the way you use,store and protect your filament will greatly impact it's quality, especially overtime, but here I'm interested to understand what makes a brand new, out of the air-tight package, good or bad? What to look for when you buy filament (specs,chemical,weight,...)? What are some brands that are notoriously know to make "high quality" filament?