[whpalmer4]

The OmniFocus database isn't really open and in a state of flux except for those brief instants when a change is being written, or the database is being compacted. The backup problem isn't anything like it is with certain mail programs that throw everything in a giant opaque database. An OmniFocus database is just a directory full of files that can be safely read except at the moment they are written.

That said, I have it write a backup file twice a day, plus on quit. If Time Machine happens to preserve some intermediate versions, so much the better. Disk is cheap, the files are small, and the days are too short to needlessly spend them trying to rescue data that could have been backed up, but wasn't.