SQL Editor contents history: Infinite UNDO possibility.

SSMSBoost regularly makes backup snapshots of currently opened document to disk, providing you with the possibility to get back to older versions of your work in future. It is not only "backup copy", it is modification history (sometimes you want to restore some specific version of your script).
The feature is disk-size optimized: No data will be written if there were no changes since the last snapshot.
History is saved on disk in simple text format, however, we have added advanced search functionality, that allows you to search for previous versions of current document right from SSMS environment. Search results can be compared to currently opened document with your favorite FileDiff tool, like WinMerge.

SSMS editor history search

Make sure you check Settings on this feature, to perform fine-tuning to your needs:

SSMS editor history settings