I don't use the backup options in the Options palette. Instead, I turn on backups in XaReg, which essentially creates incremental iterations. Because I save frequently, the number of iterations/*.bak files is large, so every so often I drag them into a 'bak' subfolder under the current workfolder. When I'm pretty sure I'm done with the project, I dump some or most of the bak files. Sounds like a hassle, but it's proven to be invaluable on multiple occasions.