Sweet Potatoes in Peanut Butter

I use estimated measures in all of my cooking, as well. I make my food according to taste and smell - it's very rare I will follow a recipe with measurements, unless I am baking a cake or something (because that can go horribly wrong if you don't measure the ingredients). Everyone has different likes and dislikes - some people like salty food, some like spicy, some like sweet - so any recipe I'm given, I tend to tweak it a little bit to suit my taste - it usually works best that way - and as you said, you get to know how much to use by experience.