I have seen a number of posts on the question of using DNS caching to get faster page resolution. From the thread, the suggestion is that caching is a technique above that of simply naming a primary and secondary DNS server. There is actually software that identifies the fastest performing DNS servers. Wanted an informed opinion outside of that thread
DNS caching is just that. Once it resolves it, it'll cache what it found. The owner will update the record and the cache will be updated as needed.
Instead of hitting the server each time for a website like www.google.com, it caches the info. If that site changes, the cache will be updated.
No reason is creating unnecessary internet traffic. Your computer will also cache DNS entries. If it fails, it'll send the request to another DNS server in which the cache on that DNS server is updated along with your computer.