How often should you measure your body?
You've got access to a professional measurement device that can give you validated, accurate results. If you're tracking progress, you might be tempted to measure yourself every day - but this isn't really necessary!
Your body weight fluctuates throughout the day due to activity and diet. For example, drinking a liter of water will increase your weight by 1 kg, but that weight isn't actually truly part of your body yet - some of it may indeed be absorbed, but some of it will become urine. The same goes for food.
This is why most experts will say that what really matters is making sure your measurements are consistent. If you measure first thing in the morning today, but measure tomorrow after enjoying a big meal, you might see a big difference in weight - but it doesn't really mean your body has actually changed. It just means you ate a lot of food! Of course, if you keep eating like this long-term your weight will indeed increase long-term as well, and a scale will indeed tell you that, but not based on a one-time measurement.
This applies even more so for body composition scans! Your overall weight might indeed fluctuate day-to-day, even if it doesn't mean anything significant. But body composition (for example: body fat percentage) doesn't actually change quickly. If you've started a program to change your body composition (ex: fitness training), most people will notice a change in composition within 2-4 weeks, depending on your level of training and dietary control.
So in general, we'd recommend measuring yourself once every 2-4 weeks to track and monitor progress. Measuring more frequently is unnecessary for most people, and may cause you to focus too much on the numbers and not the actions needed to create or maintain change. Perhaps what's even more important is ensuring that each measurement is conducted under similar circumstances (ex: always in the morning, before vigorous exercise), as the effects of exercise or digestion can in fact have an effect on results!
