Sophia: I agree that there is no necessity of seriously keeping track of work until about Grade X but there is a certain satisfaction in seeing a progression in work.
Here's how I settled the problem: Each course that my child took is recorded. The date started and the date completed. If there are tests the marks are listed by date. If you are ever in a position wherein you need a transcript made up this helps.The work - scribblers, workbooks, whatever - are discarded.
This was all done on looseleaf using labelled separators for each subject and kept in a binder. The binder was good because you could insert or remove pages as necessary or rearange the order without too much trouble. And the materials are cheap and available. Each child then ends up with a binder as a record of work completed.
At the same time I kept on file a description of courses and the materials used in case questions arose. I even indicated where I purchased the course and how much. Just for my own information. I would also write up why a course was discarded in favor of a better one. (You forget these things!)
It's fascinating to go through the binders now and see the amount of work each child completed. Their extra curricular activities were also included with the awards noted. This helped with resumes later on.
As for the artwork, you could just keep the best ones and discard the rest. I had my children work in a wire scrapbook and that stands as their art record. They can do with it what they wish.
Yep, you can certainly overdo the keepsakes.