How long does it take for AI engines to notice changes to my site?

There are two clocks running. Assistants that fetch pages at answer time — ChatGPT with browsing, Perplexity, Gemini with Search grounding — can pick up a change as soon as their crawler refetches your page. In practice that is days to a few weeks for an active site.

The slower clock is training data. A model's built-in impression of your brand only updates when a new version is trained, which is months apart and outside your control. If an assistant is answering purely from memory, a homepage rewrite will not show up quickly.

This is why the highest-leverage fixes are the ones that help live retrieval: clear category statements, FAQ content with schema, an llms.txt file, and crawlable pages. Those get read on the next fetch.

Third-party signals are slower still, because you are waiting on someone else to publish. Start those early — they compound while the on-site fixes deliver quickly.