There is a very simple way to get both maximum cache (without cache round trip, I.E. the ETag or Older-then) and reliable deployments - use version identifiers

There is a very simple way to get both maximum cache (without cache round trip, I.E. the ETag or Older-then) and reliable deployments - use version identifiers on the url and no expiration cache. The only thing that the browser should always load is your base html, and have a single linked js/css that is concatenated and compressed, whose url changes every deployment - most web frameworks already have a way of doing it (Rails, Django etc...).