Just bought an expensive mechanical (automatic) watch for a friend (a Stowa). It would be good for him to read up on the basics of mechanical watches (basically: danger signs to watch out for, proper maintenance, and maybe a little bit about how such watches work). For example, on many watches, you should not adjust the date between 10pm-2am (or thereabouts) due to damaging the date-changing mechanism. This is an example of small things to know when you own your first mechanical.
I was wondering if there were any standard (free) suggestions?