Although the IRS has never required you to complete Form 8606 Part I when for years when there was no change in your basis, the instructions for this form originally only indicated when you were required to file the form. Beginning with the 2001 Form 8606, the instructions where changed to say to complete Part I only when one of the listed requirements were met.
The instructions for Form 8606 have always said to keep a copy of any Form 8606 that you are required to file, to be used if it ever becomes necessary to verify your basis. A Form 8606 Part I that shows nothing but an amount on lines 2 and 14 does not provide sufficient information to justify basis, so it is superfluous.
