First, create a set of critical data under a few gigabytes. Wait until that set is backed up. Next, add additional gigabytes of selections iteratively, sweeping a larger and larger net, only adding additional selections after the initial backup is complete. During that time, incremental backups will keep your critical files up to date, too.

Finally, include all the files you want. By staging backups (and making a local full archive or clone), you can be sure that you aren't still backing up initial files weeks in and lose some important changes.

On the plus side, online backups provide offsite storage without the fuss of rotating drives; can be set to constantly update even minor changes; enforces having at least one additional copy of files; and provides peace of mind for a regional natural disaster, which could damage on- and offsite computers and drives.

On the negative side, online backups suffer from moderate to long delays in restores; without personal encryption password, the compromise of company or a government subpoena could reveal private data; are far more expensive over the course of a year than local backups; and a company's sudden demise could render your current and archival backups permanently unreachable.