Sharing a workbook helps you and other users work smarter, but you often have to contend with settings you don’t like that are left behind by other users. For instance, people seldom work at the same zoom percentage. Depending upon their hardware and other factors, people often reduce or increase the zoom setting.
The problem is that Excel saves the zoom factor with the workbook. Regardless of how many times you reset and save the zoom factor, it’s just as likely to be different the next time you open the workbook because other users are also saving their favorite settings.
The most efficient solution is to determine the most common zoom factor and let the workbook reset it each time someone opens the workbook. Some people will still set the zoom factor to something else, but most people will find the automatic setting adequate. Simply add the following macro to the workbook’s This Workbook module:

Private Sub Workbook_Open()
  ActiveWindow.Zoom = 100
End Sub

Be sure to save the workbook after adding the macro. You can replace 100 with whatever zoom factor is the most common. Regardless of the setting each user saves with the workbook, Excel will reset it to 100 (or whatever zoom factor you specify in the macro) each time a user opens the workbook. You can use this technique to standardize a number of common environmental settings.