Recently I had to do a restore after unexpected results in deleting an old account.

Upon doing this restore, ALL of my previous backups were deleted with the only ones remaining from that day. Fortunately I run a nightly batch job that copies all of my files (including backups) to a server just in case something like this happens.

See attached screen shots for visual representation of what happened.

Image1 shows the backups that were in the backup folder prior to the restore, with the dates boxed in red.
Image2 shows the same backup folder after the restore.
Image2 shows that I have the preferences set to keep all backups.