Over time old pages, despite relevant content, suffer a loss of SERP rank, which becomes evident when using the filtering function in the Google Search console reports. Some old pages had dropped like bricks.
The causes may vary be it a new magic sauce algorithm that Google releases on the world, but also simply that old pages had become infestations of broken links | missing images | outdated components etc.
Applying a little maintenance love to such pages boosts back their SERP rank, within a few weeks the impact can be noticed. Noticing that a page created in 2005 was still attracting traffic it was apparent that many parts of it needed optimization.
Assesing how the page had held up over time made it apparent that several things had deteriorated, given changes to web technology, but also design considerations. The font size, the layout, the http links, dodgy old tracking code, lack of support for responsive devices, and not least image files called from servers that had vanished into the dark of the web. All of these items needed to be addressed for the page(s) to bounce back.
Using the very useful "Audits" feature in the Chrome browser (F12, look for Audits in menu bar) a status check was done and issues lined up. Both performance and abiding to best practices was crucial, specially since Google has been giving away plenty of hints for some time about what happens to broken stuff.
After a serious refurbish effort with new CSS, layout, and larger fonts only the bare content and images recovered from a USB backup (!) remained.
The page was ready to hit the disk again, before that an retesting of the page for comparison was done. Excellent results, but since HTTP/2 isn't supported by the hosting company + some minor stuff = no triple 100 achieved.
Page rendering performance was in the original state now reported as poor, and with it a set of issues that created a waterfall of audit failures resulting in a substandard outcome from a performance perspective. Necessary changes where made and the revamped page, with the same old content, was retested.
The performance result perfect, the updates had lowered the first meaningful paint score resulting in a faster appearance of the primary page content.
Within weeks the page SERP rank started increase, small changes evidently made a big impact to several metrics. The page SERP analytics was confirmation that the optimization effort was rewarded by an improved SERP rank, with an uncomplicated update mission was accomplished smoothly.