to avoid throwing link equity away, you might create HIGH-LEVEL IN-DEPTH TOPIC PAGES on your site and redirect (or use canonical redirects) any related expired content that HAVE INCOMING BACKLINKS, to this topic page (and keep it updated, folding content from old pages, where relevant and there is traffic opportunity, to create TOPIC pages that are focused on the customer e.g. information pages)

QUOTE:  Each piece of duplication in your on-page SEO strategy is ***at best*** wasted opportunity. Worse yet, if you are aggressive with aligning your on page heading, your page title, and your internal + external link anchor text the page becomes more likely to get filtered out of the search results (which is quite common in some aggressive spaces). Aaron Wall, 2009
QUOTE: “Another problem we were having was an issue with quality and this was particularly bad (we think of it as around 2008 2009 to 2011) we were getting lots of complaints about low-quality content and they were right. We were seeing the same low-quality thing but our relevance metrics kept going up and that’s because the low-quality pages can be very relevant. This is basically the definition of a content farm in our in our vision of the world so we thought we were doing great our numbers were saying we were doing great and we were delivering a terrible user experience and turned out we weren’t measuring what we needed to so what we ended up doing was defining an explicit quality metric which got directly at the issue of quality it’s not the same as relevance …. and it enabled us to develop quality related signals separate from relevant signals and really improve them independently so when the metrics missed something what ranking engineers need to do is fix the rating guidelines… or develop new metrics.” SMX West 2016 – How Google Works: A Google Ranking Engineer’s Story (VIDEO)
The world is mobile today. Most people are searching on Google using a mobile device. The desktop version of a site might be difficult to view and use on a mobile device. As a result, having a mobile ready site is critical to your online presence. In fact, starting in late 2016, Google has begun experiments to primarily use the mobile version of a site's content42 for ranking, parsing structured data, and generating snippets.
There are a lot of definitions of SEO (spelled Search engine optimisation in the UK, Australia and New Zealand, or search engine optimization in the United States and Canada) but organic SEO in 2019 is still mostly about getting free traffic from Google, the most popular search engine in the world (and almost the only game in town in the UK in 2019):
QUOTE: “Duplicated content is often not manipulative and is commonplace on many websites and often free from malicious intent. Copied content can often be penalised algorithmically or manually. Duplicate content is not penalised, but this is often not an optimal set-up for pages, either. Be VERY careful ‘spinning’ ‘copied’ text to make it unique!” Shaun Anderson, Hobo, 2018
I do not obsess about site architecture as much as I used to…. but I always ensure my pages I want to be indexed are all available from a crawl from the home page – and I still emphasise important pages by linking to them where relevant. I always aim to get THE most important exact match anchor text pointing to the page from internal links – but I avoid abusing internals and avoid overtly manipulative internal links that are not grammatically correct, for instance..

SEO is the practice of optimizing websites to make them reach a high position in Google’s – or another search engine’s – search results. At Yoast, we believe that holistic SEO is the best way to rank your website because you focus on making every aspect of your site awesome. Don’t use any black-hat SEO tricks, because eventually, this will have negative consequences for your rankings. Instead, practice sustainable SEO, with your user in mind, and you will benefit in the long run.