Seer Interactive did a follow-up content freshness study one year after their original. Not surprisingly, content freshness still matters. But they add some helpful nuance and include a bunch of "here's how to put it into practice" type advice as well. They only looked at Gemini, ChatGPT, and Perplexity for this study. Here's a preview:

• 75% of web pages cited by LLMs were *updated* in the past year

◦ In contrast, 42% of cited pages were *published* in the past year

• Updating a page gets you a one-month "citation spike"
• The more consistently a web page is cited, the older it tends to be

So what you want is a collection of established, high-quality pages that are kept "reasonably fresh" (which varies by vertical, page type, and AI platform) for citation consistency over time.