It's essential to carefully protect all your software and regularly back up the data on all your disks. Determine a schedule for full backups by considering how frequently your data changes. It is an excellent idea to have three full sets of backup tapes or data cartridges and to store one set at another location to protect against fire, theft, or some other disaster. The full backups should be coordinated with periodic incremental backups. The incremental backup, which copies just the files that have changed, normally runs very quickly and takes just a minute or so.
Many people find that an incremental backup run at the end of each day works quite well.
This way their data is protected should anything happen overnight. One rule of thumb for incremental backups is to do them when it would become difficult or not cost effective to re-enter the data. Make sure you use reliable backup hardware and software. Periodically test by restoring from a backup . Too many people have discovered that their backup program couldn't recover their files when it was too late.