Why does Browser still sends request for cache-control public with max-age?

Question

I have Amazon S3 objects, and for each object, I have set

Cache-Control: public, max-age=3600000

That is roughly 41 days.

And I hav

Answer 1

If the HTTP Response contains the etag entry, the conditional request will always be made. ETag is a cache validator tag. The client will always send the etag to the server to see if the element has been modified.