In a way, the process of upgrading the Concord Advisory Group website from Drupal 6 to Drupal 7 started when Inforest initially built the site. In planning out the choice of modules used in building the site, Inforest intentionally chose to focus on utilizing two of the most common modules, the Content Construction Kit (CCK) and Views modules. In addition, Inforest built the site design using the Zen base theme, which made it easy to apply the site design using CSS techniques, with little to no modification of template files.
Part of these building choices were driven by concerns for the inevitable update of the site to Drupal 7, which can be onerous, especially if a site is dependent on custom or obscure modules that have not been updated to work with the newer version of Drupal. In the case with the Concord Advisory Group site, the choices in developing the initial Drupal 6 version of the site paid off, with only minor updates required to pages utilizing the Views module and CSS stylesheets.
It can also be said, that the overall decision to build the site in Drupal paid off as well, because when Concord Advisory Group decided that they wanted to reorganize portions of their site, including revamping their Publications section, the cost of making these changes was substantially lower than If Inforest had to rework custom code.