Thread Tape

[FatboyHK]

Should I apply them in every fitting? Will there be any bad consequence if I overuse them?

 

[Arcygenical]

Use them on plastic fittings wherever possible.

They're not generally required, and overuse makes it impossible to screw the barb in properly.

 

[ikellensbro]

If the threads are NPT, you probably should. Most modern water cooling companies use fittings with some kind of O-ring sealing the threads, but it can't hurt if you want a little extra piece of mind. Just don't let any little bits get into your loop, it won't be the end of the world, but you'll end up with a little bit of gunk lodged somewhere in your loop.

 

[Gyrfalcon]

Also make sure you put it on the right way...

 

[Ranker]

Should I apply them in every fitting? Will there be any bad consequence if I overuse them?

Not really needed until its plastic barbs like someone mentioned. Only other possibility is when the threading doesn't match up perfectly like Swiftech's insistence to not use BSPP.