During a stressful 4-6 months of college, a girlfriend who took up baking, moving countries and getting a new job I gained 40 lbs. Part of the reason why I gained so much so fast is because my scale was lost, I wore loose clothing and I was too busy to buy another scale. It took a year or two of on and off dieting to lose it all.

That is why you want these kinds of metrics, because shit like this can sneak up on you. And losing weight is way more work than gaining weight, at least for me.