OK. I just watched a video on Time Machine Basics on the Apple website. It only said that it backs up every hour. Nothing mentioned about scheduling like you can do with Super Duper. Thanks again.
Rita
That's why I quit when I did, Rita.
I've both run across a coupl'a 3rd party Time Machine scheduling apps and seen mention of TM having a built-in mechanism, so I suggest that you wait for further input.