Improve SEO with updates
Search engines rank recently updated pages higher in their search results listings. Search engines can see when you last updated a page, and they don't like to suggest pages that are possibly outdated.
In fact, Google tends to show the last time a page was modified, directly in its search result listings (see image below). This allows people to gauge how up to date your page is, in case that matters to them in the context of their search.
A recent page update gives a search engine confidence your content will be fresh, accurate and therefore useful to anyone it suggests your page to.
While weekly content updates are impractical, you should aim to update the content on your page once a month. This could be something as simple as replacing a photo or video with a new one, slightly editing a line or posting a new news article if it's been over a month since your last.
With so many pages on your website, it is inevitable that some of them won't have recent updates, but you should concentrate on your most important pages, and make a slight change to them once a month. And always set content reminders on pages with time-sensitive or topical content.
Fill in your "last modified" metadata field
T4's metadata section allows you to input the last date you modified your page. Filling in this field will ensure that a search engine knows (and accurate displays) the date of the last modification to your page.