How often do thin lugs break off?

You are correct in the assumption that less material does mean an intrinsically weaker design. That said, watches rarely receive a consequential impact on the lugs: the case protects from top impact, and your arm is in the way of any realistic side impacts. The only concern of note would be the case or strap getting caught, putting force on the lugs from the strap. But in that case, the designed point of failure would be the spring bars. They should fail before any damage to the lugs occurs.

That said, this is purely an educated guess based on material physics. I have zero experience with a Nomos, and generally do not put any watch through such severe impact, so I wouldn't really know first hand. I have yet to even break a spring bar.

The lugs on the Radiomir models can be removed with a screwdriver allowing the owner to swap straps at will. You can buy replacement lugs on line if they're damaged. As for other models like Nomos, I'd be shocked if they had issues. I've never heard of any.

Nice 

Extra peace of mind wouldn't hurt, I reckon. Still, I agree that the type of impact capable of damaging the lugs is quite unlikely. Thanks for the detailed response!

I have never heard of any lugs damage. I believe that will be a "no go" for a watchmaker and user. If we are speaking about Nomos and Panerai, certainly a hard image damage if a lug breaks ...

My thinking would be almost never.  Now ceramic watches on the other hand.... 

True, though I'd imagine the clientele would be aware, or at least would be made aware, of the potential for damage

As may have already been discussed, I think the spring bars are usually the point of failure and not the lugs of a watch. The amount of steel and thickness is much less for the spring bars, compared to the lugs of most timepieces. 

Good thread :)

I just joined, so I'm coming to this late, and I just ran into this. I own a Nomos Metro, and I can't tell if anyone in this thread does, so I might as well respond.

The wire lugs are quite solid, and it never occurred to me to worry about them breaking off. You would have to go to a lot of trouble even to bend them, like, you would have to try really hard, and you would probably bend the case too. If you actually did somehow break them, and I can't imagine how that would happen in the normal course of things, you would also have done a whole a lot of damage to the rest of the watch, and possibly destroyed the case. I've never heard of anyone breaking the lugs on any watch, and it's not much more likely here, so breaking them is really not a concern.

Glad to hear some info from an actual owner of such a watch. Thanks a lot!!!

My father-in-law is extremely hard on his watches (walking the border of negligence; I feel like every few months he’s asking me to take one of his watches in for repair due to dropping them on his tile floors). But for all the wear/damage he’s put on his Radiomir, he’s never come close to damaging the lugs. Given the thick case shape and raised crystal, as well as the fact that the lugs usually have a strap attached to them, there’s almost no way the lugs would take a direct enough hit to cause significant damage. Also, since they’re steel and not, say, ceramic, they‘d be more likely to bend than snap anyway.