Capacity planning is not a trivial task. Choose your hardware vendor and equipment carefully, and upgrades will pose few problems. Choose the wrong vendor-model combination, and you will be forced to make extensive changes to your hardware and operating system that will entail extensive planning and testing, and could ultimately require all new equipment. So how do you, as a customer, set yourself up for a successful collaboration with your hardware vendor - one that ensures the final system design meets your current requirements and adequately scales over time? This article describes the capacity planning process, some basic tools and techniques employed by the vendors, and how you can ensure all of these items work in your favor as you attempt to size your SAP R/3 system.