If you run a lot of Windows scheduled tasks, particularly on a server, it is very worthwhile to have a local account dedicated to nothing but this. The reasons being:

• If you run the task as a normal user account and that user happens to be logged when the task starts, the process runs in the current user’s session. If the user logs out while the task is running, the task quits and doesn’t complete.
• Changing an account password doesn’t effect the scheduled task account at all.

When you create a scheduled task account, it is best to assign it a long random password since you will not be using it hardly and to lock down the permissions as much as possible. For example, you would probably want to eliminate remote login for this account or just give it “Backup Operator” permissions.