At last! Someone who uses Teflon tape and knows what he's doing. I just retired after 35 years as a plumbing / HVAC tech. So many of these You tubers don't know what they are doing.
Lest you think I leave without a criticism, he did not mention that you should always use paste dope on gas lines, never Teflon. It may be different in your jurisdiction, but the gas company does not allow tape dope here in Pennsylvania. He did show several instances where you ought not dope at all. That upped his cred with me. I will say, a light coat of paste on some troublesome compression fittings has gotten me out the door and on to the next job.