Just how durable is IWC's RC coating? IWC XVIII Le Petite Prince purchased from Watches of Switzerland in August 2017. Returned in Jan. 2018 as the AR coating was rubbing from the edges of the crystal. The crystal was replaced and returned. September 2018 the issue returned and the watch sent back in December. This time IWC with the comment: "No manufacture fault. Watchmaker advised the crystal is rubbing on something to cause the AR coating to wear away...last replacement was at cost as a goodwill gesture" Cost for repair AUD500. So the owner is a pilot in the USA and wears a short sleeve uniform and an occasional jumper or jacket with soft cloth sleeves - but 80% of the time nothing to rub on the crystal and worn in rotation with another few other watches a Speedy and a Bulova Moonwatch, Seiko and Acutron. Kept in original box when not worn. Is it possible that the durability of the IWC AR coating is that fragile that a light sleeved shirt or jumper would rub it off so easily? If so it may need to come with a warning: DO NOT wear with long sleeved articles of clothing. Very disappointed as it was a gift for graduating to the "big" planes. I would have thought that if they believed it was a sleeve issue then they would have advised as such on the first return and also advised that they were replacing as good will. As far as I see it, the AR coating is not fit for purpose if its durability is that much in doubt. I guess that the top AR could always be removed but he likes that as it has a blue tinge and it was one of the selling points of the watch.