It's important to track your progress!
One of the greatest benefits from working with a personal trainer is your initial and follow up fitness assessments. Your initial assessment establishes your baseline and your follow up assessments track your progress. When you see improvement you feel motivated to continue and push forward. If you are not seeing improvement you and your trainer can reassess and make adjustments to your plan. Now if you are not working with a trainer and you are only monitoring your progress with the scale you can find yourself feeling defeated when the numbers are not changing as quickly as you would like. As a result you start to slack on your plan and find yourself starting all over again. The more information you have about your body the more milestones you can track and achieve. Any win can serve as motivation to keep fighting when you feel like giving up. So what information should you track:
body weight (it's important but not the only factor)
body mass index (important health indicator)
lean body mass (essential weight)
basal metabolic rate (the number of calories your body burns at rest over 24 hours)
hip to waist ratio (used to determine overall health risk)
Along with these factors you should track your posture both standing and sitting
As you move along your fitness journey you should find these factors improving but they will change at different rates. For example you will not see the number on the scale change as you replace fat tissue with muscle but your basal metabolic rate will improve. Monitoring your progress is very important to those who need extrinsic motivation, without the reward of seeing changes it will be very easy to quit and no one wants to fail or start over.