I use torque wrenches on critical fasteners just about any time it is possible. I have a tendency to over tighten things on any kind of threaded fastener. With spark plugs, access is sometimes limited so you have to wing it. If you have the tool, why not use it? I'm not on any time clock while DIYing. Another OCD thing I do when a torque wrench is not an option on a critical fastener is put a punch mark on the nut or bolt and at least tighten back to this mark. If I feel it was too loose to start with, at least I have a reference and might adjust it tighter. I've also been known to put sharpie or paint marks on things that tend to vibrate loose so that I can easily do a visual walk-by check. I've had things loosen on my workplace ag. equipment, so I am a bit paranoid and try to keep an eye on things that can go awry.
I use antiseize occasionally and very sparingly. Its a judgement call. I also coat some parts very thinly with a water proof paste lube to eliminate rust: hubs, rotor hats, etc..