A macro can save repeated effort, but it can also apply the wrong change quickly. Treat VBA as code that needs review and testing, not as a harmless recording of clicks.
Keep the scope small
Describe the task, input, expected output, and conditions where the macro must stop. Use explicit workbook and worksheet references instead of relying on the active selection. Split validation, transformation, and formatting into understandable procedures.
Make problems visible
Check required sheets, columns, and values before changing content. Handle expected errors with a clear message and an exit path. Avoid suppressing all errors, because a quiet failure can leave a workbook partly updated and difficult to diagnose.
Test with controlled files
Use synthetic data and a disposable copy. Test normal input, missing values, wrong sheet names, and unexpected columns. Compare the output against a manual baseline and verify that the original file is preserved.
Review before enabling
Follow organization policy for macro-enabled files, trusted locations, signatures, and external documents. Do not enable unknown macros just to view a document. A training macro should never be connected to real records without authorization and a separate review.