Modifying

Saving your changes

When you make changes to a workbook and try and close it you are prompted to save your changes.
If you make any changes to the VBA code in an Excel add-in, you will not be prompted to save these changes when Excel closes.
You must always manually save your changes first before closing Excel.

When changes are made to an add-in you will not be prompted to save your changes when Excel closes.

The Visual Basic code contained in an add-in can be compiled before the workbook is saved. Code in a normal workbook is not compiled until the code is run for the first time.
Therefore Visual Basic code contained in an add-in can run slightly faster.