What's the Most Variabilty You've Seen in Your Measurements

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I started with a personal trainer at the gym 4 weeks ago and have been monitoring my measurements very closely. I have ups and downs and don't know to what degree my progress is accurate versus measurement error. I'm guessing it's a little bit of both. I'm curious as to what the biggest variability you've seen in these measurements:

Waist
Hips
Fat Percentage
Weight