User-Friendliness – This is probably the most important element. If every time you step on the treadmill, you have to spend 10 minutes pressing buttons, it's not very likely you'll stick around for long. Find a machine that gives you options but that also has a few basic pre-set programs that you can launch in less than three steps. This usually comes in the way of a "quick start" button, but it can also be through a manual start or a pre-set walking program. Finally, make sure the treadmill allows speeds of at least 8-12mph. You may be a walker now, but if you ever decide to bump it up, you'll need that much for running routines.
User Profile – A feature that allows you to store personal data and workout information.
Pre-Set and Custom Workouts – Unless you're an expert when it comes to fitness and can adjust the settings on your own, pre-set programs give you a variety of choices, including interval programs, cardio, fat burning, hill, etc. Of all programs, interval training may be the most important --It allows you to mix periods of high and low intensity, increasing fitness levels quicker and more efficiently.
Fitness test – A pre-set program (usually 5-10 minutes long) that takes you through different levels of intensity based on your heart rate, speed, distance, etc. Great to evaluate progress periodically.