This works. Thanks for your help.

Sub FormatNextDue()

Dim Cell As Range

For Each Cell In Intersect(ActiveSheet.UsedRange, Columns("C:C"))
If Cell.Value = "HOURS" Then Cell.Offset(0, 3).NumberFormat = "0.0"
If Cell.Value = "MONTHS" Then Cell.Offset(0, 3).NumberFormat =
"mmm-yy;@"
Next Cell

End Sub