Took me three weeks to learn that wires hate my solder iron tip
I kept getting cold joints on a fuzz pedal build, swore my iron was bad. Replaced the tip twice, bought a new station after frustration. Found out the issue was I was using lead-free solder with a tip meant for leaded stuff at 700F. Switched to a proper tip and knocked out every joint clean in one evening. Anyone else waste time blaming gear when the real fix is just reading the solder spec?