Every time you buy a new set of arrows, they tend to differ by half an inch or so, if not also the make of arrow.
How critical is this kind of difference for hunting purposes?
Lochi.

If they are the same spine or shaft dimensions ie 2315, then 1/2" wont't make much differnece for hunting. If the weight of the shaft is greatly differnt, then you'll notice some change in drop. If you have a mismatched set, then I would select all of one for a partial quiver to carry. The best way to see would be to shoot them all at a target around 40yds and see if there is a consistent difference. When I was shooting 2315's out of my Lightning, then I could shoot a 2317 and it would only drop about 3" at 40yds. I now shoot carbon's, they are either straight or there broke.

Lochi-
It depends on quite a few different factors.
If you shoot a new style, fast compound then the arrows you use can be very critical.
The faster the bow and the lower the brace height, the more critical the arrow flight will be.
Many will nock up a bare shaft and shoot it through paper at about 5yds from your shooting position.
This will show you how the arrow is coming out of your bow- IE if it is flying straight, nock left, right, up or down. Then fletch the arrow with vanes or feathers and try the test again. There are many things you can do to change the flight of an arrow out of a modern, fast (265-300+fps compound).
If you shoot plastic vanes as opposed to feathers then the arrow flight/tuning of the arrow will be more critical.
There are arrow charts from each of the arrow manufacturers that tell you which arrow size to use for the type of bow you are shooting, and the draw length the arrow will be used at, etc..

I�m old school! My hunting compound is a long (by today�s standards) old style (1981) fingers shooter bow that is 55/28# 42% break over. My recurve is 62� 55#. I can shoot the same 2018s or 2117s with 5� 3-fletch feathers out of either bow. They all shoot perfect from either bow. My recurve shoots about 190fps and my compound shoots about 215fps. I shoot both with a finger tab. I�m not a fan of releases. But I was a competitive freestyle-limited (fingers) shooter from the late 50s through the early 80s.

One advantage of my old style heavy aluminum feather-fletched arrows. Just like bullets, mass weight is what delivers the kinetic energy to the animal. My arrows weigh 565grains with the broad heads I use. By today�s standards, that�s a HEAVY arrow. On a deer or hog, both of my bows shoot these arrows through the animal at 40yds or less.