mxdperfstat is a simple command line tool which will measure the performance (draw time) of your mxd (as a whole and for each layer) for a variety of scales (by default 100,000,000 to 1,000) at a point you can define. This is an invaluable tool in preparing to publish a map service, as it helps you identify layers of concern, provides recommendations for fixing them, and allows you to compare alternative options in a consistent quantitative way.