If possible, have the portfolio bound so that nothing can be lost. A title page is customary and should include the date your portfolio was completed. You might want to consider adding page numbers and a table of contents. Do not consider these if you intend to make changes to your portfolio in the near future. To avoid having to learn all about portfolios when it's time for your student to apply for college admission, you might want to get in the habit now with your younger students.
Portfolios are very similar to scrapbooks.
These make wonderful keepsakes, but if you are worried about space, they could become treasured gifts to grandparents or other friends or relatives. In this case, the introduction might be a dedication to the recipient.