I use binders.
1) One for doctor's reports, with tabs for each doctor and a calendar at the front recording who I went to and when (I also put a summary of what was said at each visit and any questions I need answered
2) One for stuff from the ALS society- info sheets, lists of resources, etc
3) One for receipts- all costs pertaining to whatever it is I have
4) One with important documents such as the (as yet uncompleted) health directives, PoA, etc, etc, and will add other official and legal stuff as time goes by
5) plus a smaller one with the most recent imaging copies and anything I think would be needed for seeing a new doctor, just in case
I'm sure my collection will move into a file cabinet at some point should it get really cumbersome.