There are many sources of information about best practices using JMX, focused primarily on common usage conventions and design patterns. However, the use of JMX in custom application monitoring systems brings with it an array of unique challenges involving the aggregation, analysis, and visualization of real-time data. This paper discusses practical issues regarding data content and design of MBeans for optimal use in such systems. Some commonly overlooked requirements are explored and recommendations made for minimizing client-side development efforts.