Reply To: Does ID store date/time of last redefinition of styles and can it compare?

A very inexpensive safety net is GridIron Flow. It will automatically save versions as files are overwritten so that you can revert (pretty much instantly — we're not talking about restoring from a backup) to an earlier version any time. Visual versioning is a life saver, and a bonus is that you can make any saved version the current one just by a click, open it and re-sync. Flow has other advantages in a design workflow, but that one feature has saved my bacon (and a great deal of time) more than once.