I used to be a purest and I washed everything before using. Then common sence took over. If I buy a kit or any of the Jelly roles that are the rage these days, I know they are not prewashed. I typically buy good fabric from quilt shops. I have never had a problem with them running or shrinking. If I buy fabric from JoAnn's or Walmart then I will wash it. Also, if I have a question about a dark color I will test it for over dye.
Gramily