Frequently, women’s suits are sold as separates with interchangeable parts. One woman’s skirt suit might be another woman’s pantsuit — or maybe the same woman owns all 3 pieces and wears the jacket with the pants some days, or the skirt by itself other days, or . . . you get the picture. When you have matching separates (matching fabrics, buttons, etc) it pays to dryclean them together — that way the cloth wears consistently, and even if the color fades or the fabric gets nubbly, the pieces will still “match” in a year or two’s time.
The same reasoning goes for things that you throw in the washing machine, as well — for twinsets, for example, even if you wear the cardigan more than you wear the shell you should wash them both together.