Pfft!
Noise gates. A solution to a problem that doesn't really exist if you know what you're doing.
Flame suit on. Lol
This is 100% correct. I have a spare flame suit if you need it.
Fix the hums and buzzes at the source, and you don't need a noise gate.
Even the best noise gates (like the ones on an SSL console) have drawbacks. As a note decays, it gets quieter and quieter. At some point the gate cuts off the last bit of sustain on the note. So a gate reduces sustain.
Recording engineers use noise gates to reduce the decay of a drum in a large room, for example, in other words (as explained above) the gate is used to
reduce sustain since its function is shutting off the noise at a certain volume level, and the gate doesn't know the difference between the guitar signal and noise.
The famous '80s "Gated Snare" sound popularized on Phil Collins' and Springsteen's records from that era featured noise gates used at high settings. You can hear the gate shutting down the decay and sustain of the drum's resonance. Gates really weren't designed for extreme settings like that, but damn, it was a pretty cool idea, though now it's considered dated.
If you want a gizmo to increase the audible length of note sustain, use a compressor.
People say a compressor increases sustain, but that's not actually correct, here's why:
A compressor makes soft things louder, and loud things softer. As it increases the very quiet signals running through it, a compressor makes the guitar's sustain
more audible. If the guitar isn't sustaining, of course, the compressor does nothing, because there's no signal being compressed.
On the other hand, because a compressor increases soft levels, it will also increase any noise in a signal. So the best cure for noise is to treat the noise right at the source.