Whether you are just moving to Drupal or upgrading to a new version of Drupal, if you are starting with an existing website, you are facing the same problem: Your migration timeline. It will take you significant effort to move everything you have to the new system and you cannot play catch-up all the time. That’s why many people are opting for continuous migration. What does that mean? Run the migration project in parallel to your existing website effort and migrate gradually, page by page and URL by URL.