How do you find if content that's been delivered to you is done via cached pages or request actually went to the backend server and came back

how I as an user can find if am being served data from cached responses or my request actually went to the backend.

I know about a way that is by looking at header, if you find headers like X-Forwarded-For or ETag then probably it's using cache but this is not always the case sometimes I know for sure that a page is cache but still there are no headers like this.

Is there way which can help to find everytime or do you know about any other method to find if user is being served cached response or not.