Good thing about retuning is it takes about 15seconds. So why not?

I used to fly a lot of practice flights. Usually 5 flights an evening, at least 3 days a week. Competition will make you do things like that. And I got to know my engine well. And got a feel for the weather. When you get used to your model, if you pay attention to how the engine takes the needle setting, you will too. And most times can feel if the needle needs a click richer or leaner and how much. If you can't fly that much, or fly more than a couple of engines, adjusting the first flight of each session takes almost no time at all. So why not?