A timely thread.
We are in the process of choosing a new interior upholster fabric too. Our present cushion covering is less than 10 yrs old. We had it professionally sewn but ordered the fabric on line. It is navy blue and it very quickly became evident that it was not tolerant of sunlight. Ours has been the boat with the curtains drawn since that realization, and now, with fading being the only defect, we will be replacing it this winter. I don't know how you can guarantee that the fabric will not fade, other than by choosing a much lighter colour, so that may be what we do.