Do you use workbooks and want to use them for another child in the future? Most workbooks are not reproducible so what can you do? I started having my son use a transparency over the page (I clip it to the page his is going to work on) then with a dry erase marker he does the page, when done we erase it and move on to the next page. He especially likes erasing!
We put a page in a page protector occasionally, but unfortunately we didn’t start it early enough – my daughter is not a big fan of worksheets to begin with and always fusses when she has to do it in a page protector.
We’ve used page protectors too… tearing out all the pages and then putting them in protectors and into a 3-ring binder. But like the previous commentor, the pages do tend to slip around a bit. I like your idea of using the transparencies; they seem a bit sturdier! Thanks for sharing!