You still pay for cache hits and refreshes, but the cost is lower.

The default Claude cache expires in 5 minutes. If you take a short break to review the code, talk to someone, or do anything other than continuously interact with the session it's going to get evicted and start over.

You can opt in to a 1-hour cache at a higher rate https://platform.claude.com/docs/en/build-with-claude/prompt...

Also anecdotally, caching has just been broken at times for me. I've had active conversations where turns less than 5 minutes apart were consuming so much quota that I doubt anything was being billed at the cache rate.