Well... If you haven't had any problems with it yet, you may be in the same category as Most of us and will not ever have any problems.
I got mine in May of 2012, have over 10K rounds through it and am still using the original RSA. Since the Shield is my primary CC pistol, I did get a replacement at 7K rounds (and it also works fine), but I'll keep using the original RSA at the range until it starts malfunctioning.
S&W has not made any changes to the RSA.
Out of 1 Million+ Shields, only a couple Dozen Shields have had any RSA problems.
A FEW RSAs have actually come apart, but did not effect functionality at all, as long as the pistol was assembled. The problem wasn't even noticed until dis-assembly, when the RSA (reportedly) few apart in multiple directions. For those here who reported it happening, it seemed to occur around the 600 - 800 round mark.
A more common problem (but still not many cases at all) involve the rear disk becoming bent. If this were to happen, you'd know it.
For those that experienced this (like SWSIG) and kept using the bent RSA (while waiting for their replacement to arrive) the bent disk did not effect functionality. Some put several Hundred to a thousand rounds more through their Shield without any jams/malfunctions.
A couple say that their disk was bent from the very beginning, but none of these can swear that it came from the factory this way, because they did not field strip and inspect the pistol at the LGS before bringing it home (I say this because if they had, they probably wouldn't have even left the store with it
)
Speculation leads to the cause being due to either improper alignment of the RSA during assembly, or the RSA shifting, causing the rear disk to get hung up on some part of the internals during firing.
While WAY less than 100 instances of RSA problems have been reported, some people still claim that it's a poor design and buy the aftermarket stainless steel RSA.
