I'm not a fan, this looks like terrible advise. If you want to do high quality work, solder header pins onto the board and use crimp-connectors on your lead wir

I'm not a fan, this looks like terrible advise. If you want to do high quality work, solder header pins onto the board and use crimp-connectors on your lead wires. I don't use flux-core wire, I prefer to apply flux directly to the pads/pins/wires as applicable. As others have pointed out, use appropriate strain relief.