Agnosis

Definitely go first with a new spool of well-known filament. Though I have had very good experiences with old filament, I recently had an issue with a spool of PET that would not adhere to the bed, and I tried drying it out for several hours. Mind you, this same spool had worked wonderfully in the past but I don't know what happened to it. Imagine that you tried to use a spool like that to calibrate your first layer!