I didn’t really understand the explanation but a watch repair man told me that if your automatic or manual wind watch runs slow it may need to be demagnetized. He explained something about watches gradually getting magnetized by being placed in frequent contact with electronics like our cell phones and laptops. If you bring it in to be serviced they can demagnetize your watch while you wait. It’s apparently a very simple process. Of course watches run slow for other reasons but he said that was one of the most common reasons behind watches running slow.I have 2 cape cod watches, An automatic and a quartz one-
The Quartz keeps perfect time, The Automatic probably loses about 3 miniutes a month.
That said I've never had it serviced and owned it about 8 years or so.
They're fantastic watches however and much more reliable for timekeeping than my Rolex (which I have had serviced!)