Accuracy, Regulation, Break in? Myth or True?

[ttomczak]

Recently, I bought a BNIB Rolex with a 3131 movement... It lost 7 seconds a day (and yes, I know there is over 82000 seconds in a day), but I wondered about it... I then bought a GMT (used), and it currently is running at -1 second per 24 hour period.

I have seen threads on getting it regulated, some with -1 second every two weeks (really?), and that if it's new, there is a break in period...

Since all of the modern Rolex's have the COSC certifications, I have to assume ALL of our movements have been broken in, even when we buy them new... My GMT, as have most of my Rolex's, has or is very accurate, but the 3131 which was slow per my others at -7 a day seemed to be a little strange... And I get that different people make our movements, etc...

Just wondering what everyone's opinion is on this... Is there really a break in period? Is Regulation worth it? And what do most accept as "accurate"? I know we are a demanding bunch!!!

Just curious...

Thanks!