Yes. If a theme is not to be used as is, you should create a subtheme. http://drupal.org/node/225125 Then you can change only the bits you must and leave the base alone to be updated as needed.

Nancy

Injustice anywhere is a threat to justice everywhere. -- Dr. Martin L. King, Jr.

From: Tim Johnson
I'm using the mayo theme on drupal 7.17.
I modified sites/all/themes/mayo/templates/node.tpl.php

Should there be an update for mayo available and should I install
it, I presume that node.tpl.php will be overwritten.

If I am correct, is there a good strategy for preserving my code
changes?