I use scheduled tasks for a number of daily processes. They get all
the routine stuff out of the way each day before I'm even awake. The
only time they don't work is when the box is shut down or I change my
password and forget to update the scheduled tasks. It's easier to set
up and much more flexible to schedule than an Excel-only solution. You
can set it to run weekdays only, every 30 minutes from 9:00 am to 4:30
pm, you can disable it with the click of a checkbox, lots of options.

I find it useful to use an Auto_Open macro in a separate workbook ("X:
\Wherever\Scheduled Run.xls"), so that I can maintain the real macro
without accidentally launching it each time I go in to tweak. This is
it:

Sub Auto_Open()
Workbooks.Open "X:\Wherever\Your Macros.xls"
Run "'Your Macros.xls'!Run_Me_Now"
Workbooks("Your Macros.xls").Close
Application.Quit
End Sub

The scheduled task's run command is simply "X:\Wherever\Scheduled
Run.xls"

Only thing you need to remember is, whenever your password changes
(assuming you have one), update the scheduled tasks too.