I am in the school that the shoulder should be bumped back with a properly adjusted FL die everytime the cartridge is loaded. There is several ways to measure the amount of bump that the shoulder is moved back. If you buy a good custom die you will usualy get a piece of brass, or something else with it, cut to the taper of the shoulder. You simply place this tool over your case, mesaure it then size the brass, put the tool back on, and measure it again, subtract the diference, and you get the amount of shoulder bump back. You would then either adjust your die, or place shims under it to get a desired bump back. I like to bump back about .0005 to .001. I like mine on the tight side of things, but some will do .002, and it works fine for them.

There is other tools as well, having a custome barrel made by a good smith they should give you a piece of barrel with the reamer used to chamber the barrel, reamer ran part way in to make a gauge, the gauge is used in the same fashion as the aformentioned gauge. L.E Wilson makes a "case gauge" that also works in a similar fashion. Sinclair and Hornady make similare tools that will attach to a caliper, and would measure the case dimentions.

Some still go by a less accurate method and they play trial and error with the case in the gun. On Remingtons (And other like style actions.) they remove the firing pin assembly, and size the case untill they can chamber it, and when they close the bolt feel just a small amount of resistance at the bottom of the stroke on closing. Unfortinaly this method doesn't work well on savage do to the inability of removing the firing pin assemble and having a bolt that would hold togeather. If you have an action that has been reworked (T&T) you can fell this when chambering the round and make adjustements.

It is a good thing to check the amount of bump back, as there are diferent tolerances in dies, and I have found that some dies do not push the shoulder back, or will push it back too far. These dies need to be modified to correctly bump the shoulder back. If anything you should use it to properly set up your dies, just setting the die to where it touches the shell holder, doesn't properly set the die. I have also seen dies that was cut made to short right out of the box, and thay would push the shoulder back way too far and at the point, where the round could not be extracted because it was dangursly too short. Over sizing bras will lead to short life, and some beileve that it will cause accuracy problems do to the case being cocked by the ejector. With that all said, properly adjusting and setting the dies to the rifle is a must.