@bertoniNot the same watch, but I've been wearing a Sinn 556A every day for the last year; at work and at home
It depends what you do, and how you look after it, but mine's definitely not had any special treatment and is holding up well:
The stainless steel case has a couple of light marks, but still looks clean and smart.
I work in the optics industry, so maybe I'm overly critical here; it's got a couple of very faint scratches across the sapphire glass which are only visible under glancing incidence light (ie you've got to look really hard to spot them.)
In the last month or so, I've noticed a tiny mark on the face that looks like the anti-reflection coating might be coming away (they coat the sapphire on the front and back faces of the glass), but again you've got to look pretty hard to spot this. (I seem to remember reading about this before I bought it too; maybe worth a bit of research if you think this might bother you)
All in all its a pretty tough watch, looks good (imo) and is good to 1-2 secs a day (which I'm happy with)
Hope this helps