I've been following this topic, this is my 2 cents worth...
There are a few school of thoughts for drag setting. It all depends on the fishing situation. A drag is like a mechanical tool that you need to understand fully to use it properly.
I've met many angler that, give it a pull and say it is ok, It is probably Ok but are you using your drag efficiently? Also, I have heard endless time anglers saying to set your drag to a setting and should not be altered during the fight? Is it beneficial?
Just to get your mind thinking, take a rope of 2 feet and a rope of 40feet, tie them to a car and try pulling the car with the shorter rope and try to pull the car with the longer rope? You don't need a rocket scientist to conclude that it is easier with 40 ft of rope since the angle of tow is smaller with the rope when it is longer.
The above relates also to drag, a drag set at 10ft from the tip can be increased if you are fighting a fish at 90ft! Now, that is why micrometric is helpful. And it should be like clockwork in your mind to ease off your drag when you are bringing the fish nearer. Some boat anglers knows exactly how much drag increase you get from increasing 1/4 turn of their drags(you could get that easily with a scale)!
It is obviously easier to set your drag just near the tip and not be bothered to alter but you must keep that in mind if you need additional drag power to stop a powerful run.
What works for someone may not work for another! When you are targetting speed fighters on light lines like trevallies, milkfish, bonefish and tarpon that you realised you need that little extra.
I like high drag setting at the start, and I do set the drag at about a few metres from the tip. This is the worst case scenerio I'm going to come across. I came across a few anglers that set low drags and increase their drag gradually. 2 things usually happens, 1st they get line off their spool very quickly and the fish gain massive momentum and by the time they increase the drag it is harder to turn the fish and secondly as the run is massive they just tighten the drag abruptly just to stop the fish and this result in line failure.
If you get more technical, you can set you drag to a dynamic drag which is more complex but static drag setting is much more easier to understand first.
Just to have an idea, 1500 size reel have drag of about 2kg, I use a 1500 size Caldia kix which does push it to 4kg, some japanese rypbi can push it to 6kg and believe me at 4kg the caldia still delivers smooth drag! The shimano stella if I remember is about 2kg for the 2000 size series. A 4 kg drag is a good drag indeed and it can stop a shark! At 3 kg it is very hard to pull braid off your spool with bare fingers!
As for backing off your drag you should do it since it prevent the washers to seize up, but I don't back up the drag completely for the simple reason that some washers are imprenated with oils and when you back the drag completely the oils seep through the washers and they swell. The problem you have is that when you retighten again, the surface of the washer has microscopic fibres on the surface which can produce a jumpy drag at first and come back to smooth after they get working. I always back off by drag to 1/4 of their setting.
The question I asked to many anglers who understand perfectly their drag is:
How do you set your drag after you have played with the setting or changed a spool? Many of them says they use a scale but it is very awkwards to be adjusting your drag all the time with a scale and you probably need 2 person to do it?
There is a simple way to get it quite accurate and you don't need to carry a scale! :