If I understand this correctly, it sounds like the compression line that happens when you put in a sharp brim break, a 90 degree angle one. It in unavoidable, I am sad to say. The same thing happens with a really sharp front Raiders crease as well, over time. If you keep that front pinch sorta more loose, that's ok. but when you really make it razor thin, you get a lighter colored compression line, that will never come out. On reblocks, I have to locate this same line where it was originally so as to hide it.Steve, any idea what's happening at the brim/crown intersection that causes that "fold" discoloration?
If one wanted to change a hat from a Raiders fedora to say a CS, and he had that compression line on the front pinch, I would then turn the hat inside out, and finish up the inside which is now the outside to get rid of the compression line so it would not be seen on the CS hat. That is major work by the way, and I would have to charge more for that reblock, due to the extra work and time involved in this. Just so you guys know up front what this entails. I could make two hats in the time it took to do this inside out deal.
On the brim break compression lines, hey, that's been on hats for as long as hats have been made, if they put the brim break in correctly.
My biggest problem in sizing a hat involves making a hat for our black neighbors. Recently, one guy said his hair was really short, but in the future he would be growing it out into an Afro. My suggestion was that he buy two hats. One for the no hair head and one for the Afro. See, hair thickness is a variable here. The hat gets tighter if you have thick hair, and more so than if you have thin hair like me. But even with thin hair, my hat tells me when it is time to visit my local barber. So length of hair CAN be a variable.
On whether one's head changes sizes with age, or weight gain, I would say only with weight gain, and then it would not apply to all. I know you have seen fellows that were overweight, with a shaved head, and noticed that there was fat on part of the head from the obesity. Which should trim down if they lost alot of weight. So, in this aspect, I guess if an obese guy was carring around excess fat on this noggin, and he lost weight, his hat size would change a bit. But I have also seen obese folks with no extra fat on the heads either. So.......Fedora
His loss. 
