Do all pastel ball pythons bronze out or loose their color as they get older?

and why?

not all pastels brown out when they get older, some even get brighter
why.... not really sure, my guess is they just lose their color as they shed..

I think they all change colors. For some, this will be getting so brown they don't look much different than a normal. For others, this may mean losing some of the intense colors, but they will still stay bright.

Most ball pythons in general brown out as they get older and pastels are no exception. Now how much is where the difference is, some do more than others. Thats where quality and selective breeding comes in.

There are a few morphs that get lighter with age like a fire for example but most get darker.

Lemons ted to stay bright all the time