Obsolescence is unavoidable, might as well just accept it and become an expert at moving websites, without compromising previous search engine optimization, because it will happen.
Website’s owners will want a new domain, a new extension, a new CMS, a new design, all those innovative temptations will turn them on, and that is OK as long as you master the art of redirection to minimize SEO juice loss.
Here are some of the best resources we found very useful. You are very welcome. Best of luck in your 301 journey !