Add pipe dope to prevent leaks
Wrapping Teflon tape around pipe threads to create a seal is standard procedure for DIYers. But it's not foolproof. Burrs inside the female fitting can catch the tape and roll it around. The leak will only show up after you've finished the job and turned on the water. At that point, you'll have a mess on your hands, cutting and refitting pipes.
Here's a tip from master plumber Les Zell. Go ahead and wrap Teflon tape around the male threads just like always. Then add pipe thread sealant as shown. The sealant will fill any gaps caused by tape failures. It's cheap insurance against a leak. Les says he's never had a leak since he started adding this second step.