Yes I use color catchers.
Here is a picture showing one from the second wash (dark)and one from the third wash (much lighter) . I tossed in 2 for each load since I had a lot of yardage.
the first wash was with another dark fabric, and I pulled the navy out and tossed it in the dryer, but when I pulled the brown out it had a blue tinge to it. Then I realized I'd forgot to put color catchers in the wash! So I put the brown back in with a couple of color catchers and ran the wash cycle while I dried the Navy. the color catchers in with the brown came out quite blue, so I ran it through a third time and that time the color catchers came out much lighter and the fabric didn't look blue anymore. Made me realize there must still be a lot of dye in the navy, so after it was dried I tossed it back in the wash, and the catchers came out so dark that I ran it a third time.
But my "experiment" really did show how much die the color catchers grab on to. I've also beleived that drying would help set the dye, but it really didn't.