Personally, I wear sporrans only if I have insufficient pockets in my jacket, or whatever else I am wearing. The sporran is, after all, only a pocket. Of course, I am talking here of tartan kilts. The only exception is when I am wearing the full rig, probably for some official or semi-official event - then I would wear the sporran because it is part of that 'costume' or 'uniform' (how I hate those two words!).

As for my non-tartan and other contemporary kilts, well I very seldom wear a sporran with any of them......... the Utilikilts have wonderfully capacious pockets anyway, so who needs a sporran? Anyway, Utilikilts are American and sporrans are Scottish - they don't necessarily go together. However, I do wear sporrans with my "TFCK" kilts from time to time, depending upon the availabilty of other pockets.

I really do not think that sporrans look 'right' with anything other than tartan or Scottish-style kilts, but I admit, there are no rules concerning this.