Establishing baseline numbers is very helpful for setting short and long term goals. It’s also helpful for measuring progress & evaluating the effectiveness of your workout plan – whether it’s losing weight or wanting to be able to do a particular number of pushups – whatever. You need a starting point to know what’s going on. However, when it comes to weight loss, I do place more emphasis on body fat % reduction vs. actual scale weight reduction. But to determine body fat percentage, I need to know their bodyweight – from the start & along the way. I hope that helps.