VBA to send email based on date

Normally I go running and screaming into the night when I see merged cells in a worksheet. But I decided that it wasn't too bad.

In column E I added the DateDiff criteria for the various pieces of equipment. You can hide this column if you wish. The code looks at the cells in column D and if a cell isn't blank it gets the expiration time from column E and compares it to the date. If it's over due, then the code assembles a subject, addressee list and a body and passes it on to a standard mail module that I use often. The list to mail to is on the Mail To sheet.