Well, yes, eventually all will get seen to, however that doesn't mean all will fail
prematurely. The prematurely part is important, and leads into this question...
Before I try to answer the question directly, I want you and others reading to think about watches a little differently. Here's the reality - from the day the watch is made and sold, it is in the process of failing. Without intervention the watch will come to a stop in some period of time, and what watch manufacturers do is try to make the mean time to failure as long as possible, and then they set expected service intervals (and to a degree their warranty period) based on that.
Does the fact that the watch stops eventually mean it's a bad design? No, of course not, as nothing lasts forever. The thing that makes it a problem for companies and consumers, is if it fails before it is expected to fail. When I think back to the time when the early 2 level co-axial escapements were causing all kinds of problems with premature stoppage of watches, Omega tried several different approaches to resolve the problem on these escapements. Eventually, they came up with a mitigation strategy that allowed the watch to run long enough that customers didn't see it as a problem. The fundamental issue still remained, and every single one of these that I have serviced has had a build up of sticky residue on the intermediate escape wheel and co-axial wheel, but it hadn't yet reached the point of stopping the watch. As long as Omega could delay this failure to a point where it coincided with other failures in the watch movement, and that was at what people considered a "normal" amount of time, it was effectively solved.
Now to the 3861. When this movement was first made and the first technical guide was released, the oiling of the center wheel bushings was what I would call a normal amount of oil, so the same I would use on any other center wheel, like the 1861. So I can't show the Omega documents, so I'll illustrate what a typical call out for oiling the center wheel on a watch looks like, using the publicly available tech guide for the ETA 6497:
The green arrow I've added points to the oiling instruction for the center wheel. This strange looking symbol tells me how much oil is supposed to be applied to this location. The original 3861 technical guide looked like this, but the later version released looks more like this mock-up I've made:
So now there is much more oil being placed in this location. These technical guides are for after sales service, but also reflect what is happening in the manufacturing process, so if you get a watch that has had the updated oiling procedure, it may take much longer for the issues on the center wheel to materialize. In fact, it may never fail
prematurely. This additional oiling, like the mitigation used on the 2500 series calibers, may be enough to extend the service interval of the watch to what is considered normal.
The next question is, why the change in bushing material then? Well,
if the root cause is the bushing, then it should be changed, but I will note that even with the new bushing, the instructions to add more oil have not been changed, so it still calls for a lot more oil in this location. Omega doesn't give detailed reasoning for these things, but only practical instructions for how to solve the problems, so it may very well be that the new bushing is something they are doing proactively - only they know for sure.
So it is very possible that some of these will never see this problem at all, or when they do it will be time for servicing anyway.
Cheers, Al
