AutoRunning Upon Open Issue - vba

Question

First off, I'm not very savvy when it comes to programming in VBA. I've done a lot of programming in the past in Java, C++, C#, and a few others so I'm not completely new to programming in general.
My current issue is that I have an inventory list that I want a notification to be emailed from once a certain quantity has reached a certain value. The email notification is setup and working fine except when the worksheet is closed then reopened, the notification will be sent again if the value has not gone above what was previously set. For example, if the quantity is at or below 1, a notification will be emailed. If that quantity is not changed to 2+ before the worksheet is saved and closed, the next time the sheet is opened, the notification will be sent again.
I want to limit this so that only when the quantity is changed for the first time then the notification is sent.
Code below:
Public Function EmailNotification(model As String, color As String, cell1 As Range)
Dim OutApp As Object
Dim OutMail As Object
Dim cell As Range
Application.ScreenUpdating = False
Set OutApp = CreateObject("Outlook.Application")
On Error GoTo cleanup
If cell1.Value <= 1 Then
'For Each cell In Columns("R").Cells.SpecialCells(xlCellTypeConstants)
'If cell.Value Like "?*#?*.?*" And _
'LCase(Cells(cell.Row, "S").Value) = "yes" Then
Set OutMail = OutApp.CreateItem(0)
On Error Resume Next
With OutMail
.To = "username#domain.com"
.Subject = "Excel Notification: Toner Renewal"
.Body = "Dear Team," & _
vbNewLine & vbNewLine & _
"Please prep an order for " & color & " toner for a Dell " & model & vbNewLine & vbNewLine & _
"Quantity Remaining: " & cell1 & vbNewLine & vbNewLine & _
"Notification Sent: " & Now() & " from " & ActiveWorkbook.FullName
.Send
End With
On Error GoTo 0
Set OutMail = Nothing
'End If
'Next cell
End If
cleanup:
Set OutApp = Nothing
Application.ScreenUpdating = True
End Function
cell1 is the quantity that gets checked in the function.
I'm not sure if there is a way to halt this AutoRun at the startup then allow it to run again whenever one of the quantities is changed.
Thanks in advance for your help!

Answer 1

I'd take a cell in your workbook (say cell2) and store a boolean to say if the email has already been sent once or not.
Your function would look something like this:
Public Function EmailNotification(model As String, color As String, cell1 As Range, cell2 As Range)
Dim notifSent As Boolean: notifSent = cell2.Value '<-- get the value of cell2
If cell1.Value <= 1 And Not notifSent 'if quantity below threshold and no notification yet sent
'you send the email for the first time...
cell2.Value = True 'and you set this information in your cell
ElseIf cell1.Value > 1 And notifSent 'if quantity above threshold and notification has been sent before
cell2.Value = False 'reset notification to false
End If