Yes, I always measure. First, to get consistency so that every time I cook a dish, I can count on it's flavor and presentation. Second, baking is a science and you don't get as good results if you don't measure. Third, I'm diabetic and have to count carbohydrates. I have all of my normal recipes written out with the carb/fat/protein, etc., count written on the recipe so that I know exactly what size a serving should be for me.
But here's the biggest reason I measure: cost. People who don't measure tend to use 3 times as much of an ingredient as is needed. For something like salt, that isn't expensive. But for something like vanilla extract or butter, it is expensive. Spices cost a lot, too, and if it doesn't significantly improve the dish by adding three times the spice, it's a waste of precious money to just pour without measuring.
Measuring is a tool of the tightwad.