The following material summarizes how one might construct a portfolio.
Brevity is an art.
You only want to take your most impressive work samples to an interview. Also, I believe that people will be more inclined to read 10 pages or examine 10 artifacts, as opposed to 25. The lower number will also help keep the costs of printing and reproducing down. It should be pointed out, however, that your larger career portfolio may contain 20 or more items. Just cut down the final product to a 10 page sample of your most employer-relevant artifacts.