Perhaps it is worth mentioning, on the question of fugitive colours, that whereas the transitory nature of the colour appears to modern eyes in the twentieth century as a distinct drawback, in more primitive societies dyeing with a substantive dye was no more arduous than washing, and the cloth would from time to time simply be re-dipped, especially prior to a festival or some other special occasion.Ann Hecht, The Art of the Loom: Weaving, Spinning and Dyeing Across the World (New York: Rizzoli, 1989) pages 22, 23
Well, no, I didn't re-dip my cloth to celebrate B.C. day yesterday, thank you for asking, but that does sound like a fun way to get in the holiday mood.
We worry about colours running in the wash and wrecking the load of laundry. We sew seams in our clothes with thread that takes dye differently than the cloth, and if the dye gradually leached out of the cloth the thread would no longer match. It's interesting to think how previous cultures didn't have a problem with fading colour.