My 2824-2 based watch has been running pretty consistently at +6 per day. It had been running about +9 until a couple of forum members suggested I store the watch crown up at night. I was pleasantly surprised that such a small change resulted in a substantial improvement.
Up to about a week ago, I had relied completely on auto winding. But recently there were a few days in a row when I knew I would only be wearing the watch for a few hours, so I supplemented by manual winding. Then out of a developing habit, I wound it a few turns each night even though I had worn the watch all day. Unexpectedly, I have noted an increase in accuracy to about +4.
I find this counter-intuitive. I would not think that maintaining greater mainspring tension would lead to the watch running slower. Does this make sense?