From A. Lange & Soehne, A. Lange & Soehne recommends that you do not do the following to an A. Lange & Soehne wristwatch. Most of them are obvious, but all of them are serious offenses.
1. Swimming with a watch that doesn't receive regular maintenance.
2. Wearing metal chains and bracelets and a Lange watch on the same wrist.
3. Hammering, golfing, mountainbiking and whatever else will keep shocking the watch. Over time, the shocks will influence a watch's precision.
4. Leaving the watch on the dashboard in summertime. Quick changes between extreme temperatures put strain on the lubricants, thus influencing the precision of the moment.
5. Handing a Lange watch in for maintenance service with an unauthorized retailer licensee. Much damage is caused by improper repairs.
6. Correcting the outsize date between midnight and 2 a.m.
7. Not setting back the crown by a half revolution after winding the watch.
I personally follow all of the rules, except on some rare occassions, I am not supremely confident that I fulfilled action # 7. This is why I posted these rules, so hopefully other A. Lange & Soehnes are not suffering mistreatment.