John Mueller is out with another #AskGooglebot Google SEO video, this one is on site migrations and URL changes. It is a short two minute video on one of the most SEO intimidating modifications one can make to their site – alter all the URLs on their site.Here is the video: John explained that URL modifications are not easy for online search engine to deal with due to the fact that Google stores in its index a set of URLs, its on a URL or page by page basis. John stated “this might initially seem like a little change within a site.” He stated nevertheless “its not that basic for search engines.” Why? John explained that “online search engine like Google store their index on a per page basis.” “So if you alter the address or the URL of a page that pages information needs to be forwarded in some way otherwise it gets lost,” he explained.First, John advises you deeply study the Google site relocation documents, it was vastly enhanced in 2014 and updated ever since with time. John then summarized what you should do, but it is very important to see all those details in the help docs: Here is the slide with what you must do: And he said these modifications can take Google several months to process with the more vital URLs happening faster and the lesser URLs occurring slower. Google has said the majority of the time these moves take a few months but once again, John reminded us to keep the redirects in location for a minimum of a year.Forum discussion at Twitter.