Evergreen pieces are typically explainer guides, definitional content, foundational how-tos, and reference material. A post titled 'What is email marketing?' written well in 2022 can still rank in 2026 with light editing. A post titled 'Best email marketing trends of 2024' has a hard expiry date.
The economic case for evergreen is compounding traffic. Time-sensitive content has a traffic peak and decay; evergreen content slowly grows traffic over months as it accumulates inbound links and ranks for longer-tail queries.
Even evergreen content needs a periodic refresh — at minimum updating examples, screenshots, and statistics every 12–18 months. Search engines favour recently-updated pages on competitive queries, and stale screenshots are a credibility signal to readers.