However, if you run computationally intensive jobs, like science or engineering applications, hundreds of megabytes could be required for brief periods of time. This is where users home directories go. If you do not impose quotas on your users, this ought to be in its own partition. This is where your kernel images go. If you have a drive larger than 1024 cylinders, making this your first partition guarantees that it will be visible to lilo.
Files have lifetimes.
After a file has been created, it will remain some time on the system and then be removed. File lifetime varies greatly throughout the system and is partly dependent on the pathname of the file. For backup it is useful if the amount of daily backup is smaller than the capacity of a single backup medium. A daily backup can be a complete backup or an incremental backup. Your backup strategy depends on that decision.