Yeah, but it's hard to remember that you're noticing trends over time when you can visually see and physically feel your body composition improving, but the Tanita scale says you're up 2% body fat. It's an imprecise tool at best. Oh, and if you have one for all those years, it will adjust its calculations way too grossly as you change your age. Having a birthday does NOT make my body fat increase by 3% overnight.
Or just take regular measurements and photos. Why buy an expensive tool that doesn't work all that well and doesn't really tell you what you want to know when you can judge better with a tape measure and the fit of the clothes already in your closet? Neck to waist ratio, or just plain old waist size is probably a far more useful metric for most regular people who aren't figure competitors or whatever.