Logo,
I run Compact & Repair in auto mode and have never had a problem. I don't
worry about trashing my databases with a C&R operation because I back them up
regularly. But when A2007 was first released, there were alleged incidences
of auto C&R destroying folks' databases.
I strongly recommend backing up your databases before doing any operation.
You should also save your database after adding critical data. For one of my
databases I am up to version 56 and I have several backups on the internal
drive, on external drives, in the cloud, and even DVDs. It is better to be
safe than sorry.
David