I've been reading some great articles regarding SQL Server plan caching by Kimberly Tripp such as this one: http://www.sqlskills.com/blogs/kimberly/plan-cache-and-optimizing-for-adhoc-workloads/

Why is there even an option to "optimize for ad hoc workloads"? Shouldn't this always be on? Whether the developers are using ad-hoc SQL or not, why would you not have this option enabled on every instance that supports it (SQL 2008+), thereby reducing cache bloat?