Once a month!? Is that enough for you?
Make once a week a full backup with imaging software.
And once a day an incremental.
I completely disagree. That frequency may work well for you, but it is
certainly not ideal for everyone. How often you should backup depends
on how you use your computer and how frequently and how much your
files change. For example, I have a close friend who doesn't even turn
her computer on every day, let alone create or modify files that
often.
Granted that a month is a long time between backups for most of us,
but that doesn't mean that it's too long for everyone. For the kid who
does nothing with his computer but play games, it's probably much more
often than is needed. And for the person who runs his business on his
computer, once a week is almost certainly insufficient, even with
daily incrementals.