That was my thoughts. I know if you leave a piece of fabric (like a blouse,etc) in the sun or the elements it will rot. I have a shirt I made our first son 35 yrs ago and it still looks as good as the day I made it. I keep in a drawer. It never sees daylight. We had another son 4 yrs later and had his picture made in it just like the first one. The boys were about the same age (10 months) and holding a baseball in front of them. That is the only reason I have kept the shirt.
Do you think being wrapped around a spool would shortened the life span of the thread. Also if you had a piece of fabric folded for many years do you think the fold (crease) would become permanant? That really doesn't matter, as long as it doesn't distort the colors, I can work around a crease.
Curosity question: What is the longest time you have held on to a piece of fabric? Inquiring minds want to know!