DW says they don't fade as much if you wash them inside out.

I have 2 pair of jeans like that with the spandex. They are also dark blue. I've never put them in the dryer as I'm afraid they will shrink. I've never turned them inside out and they haven't faded any after several washings. I don't think I could always remember to turn them inside out. Anyway, it hasn't hurt them.

Much of the "fading" that clothing does is actually abrasion of the surface.
Washing them inside out helps as does being careful not to over load your washer.
If you have nice dark jeans you want to keep that way, wash in a small load with a full tub, inside out.
Linda C

Front-load vs. Top-load washer differences when it comes to fading?

I use Woolite for Dark colors with my dark jeans and they always come out great

I wash all jeans inside out. It really helps preserve them. This is also a good practice for sports jerseys and t-shirts with iron-on designs.