I know when you neckturn it's ideal to get the neck perfect but I'm just curious how fussy you guys get when you do it....I mean how many tenths of a thou is acceptable? 1,2,3 tenths?
Much of what bench rest shooter do in case prep filters down to us is overkill in standard off the shelf factory hunting rifles. When you are standing on your hind legs shooting at a running deer, neck turning, deburring the flash hole, uniforming primer pockets, etc isn't going to make the deer stand still and calm your heart rate.
"BUT" once you get a runout gauge and a neck thickness gauge you will learn a great deal about the quality of your brass.
So the answer to your question depends on the type shooting you are doing, the type rifle and the range you are shooting at. "AND" if your full length resizing or just neck sizing because both deal with neck tension but with neck sizing it also means the bullets alignment with the bore to a greater degree.
Below is a Remington .223 case with approximately .003 neck thickness variation.
Neck turning cases with large variances in case wall and neck thickness isn't going to align the bullet with the axis of the bore when neck sizing. And when fired these cases will warp and become banana shaped and effect accuracy also.
And I didn't make up the term "banana shaped" as you can see below.
So to answer your question if you have a custom made rifle with minimum chamber dimensions and shoot in competition then be fussy. If you have a off the shelf factory made rifle and full length resize then you do not have to be fussy about a few ten thousandths.
And the neck thickness gauge pictured above taught me more about the quality of the brass than anything else. And one turn of the wrist separates my .223/5.56 cases from being shot in my AR15 carbine or my bolt action .223.
I got the photo below off the internet but I think after what he spent for the rifle, he was fussy with his brass.