An agency that I work with a lot maintains this site, updating content, managing digital advertising, and tracking analytics. I had been doing minor tweaks and repairs on the site for about a year when the agency was asked to create two new sections on the site. The new sections were close in design to the existing site but with subtle and important changes. The challenge was to use modern, efficient, professional development tools and techniques on a site that had grown through accretion over the years while passing through multiple developers’ hands.
The big problem with older sites that have been through many hands is usually the CSS, just because of the nature of how they work. But, using the PostCSS processor through a build tool like Gulp (I realize this all sounds like gibberish) and employing a name-spacing technique like BEM, a developer can gain the efficiencies of a mostly-modern workflow while working on a legacy site. We could develop the new sections in place without worrying about CSS revisions breaking the site, making review by all the stakeholders easy and simplifying the go-live effort to near-trivial.