Traditionally only the rich had money to spend on clothes which didn't serve a purpose. The rest of the population had a shirt for the week and one for Sunday Best. In latter days they might have had kit for cricket - hence Morris dancers in white. The only way to disguise "ordinary clothes" was to attach ribbons or "tabs" of cloth.
The only way to judge what was worn is by contemporary evidence such as artists impressions - woodcut of Kemp's Jig. Of course, in that case, the costume probably had more to do with what Shakespeare's actors might wear then any "morris tradition".
Quack!
GtD.