A archive/backup save feature
I recently was working on a highly important document. InDesign crashed AT THE SAME TIME as it was in the process of saving the file. I do regular saves, but because of how it crashed I couldn't revert to an earlier saved version of my file. My new workflow is to regularly save my work and I use sequential numbers e.g. filename-v01, filenam- v02. I also sometimes will use save as and create a new file called filename-backup and then I will have to do another save as to revert the document back to filename.indd. What would suit my workflow is I continue to save my file using my standard filename but I can create a 'backup' file at any time called 'filename-copy-day-time'. The extra details in the filename would be automatically added by InDesign. This would also not affect my ability to save my working file as filename.indd.
Lance Murdoch commented
Quark has had a save feature that allows for up to 20 versions of the the last saved versions of the document accessible. The arrogance of only having 1 version that may get corrupted (I'm talking to you Error 5) is inexcusable. I've had multiple documents corrupt and be lost permanently. I last saved version that was available would be invaluable.