zOwie Omega Discussion Forum

: Hello all,

: My SMP is running -2 or so seconds per day and
: is now three weeks "old." This got
: me thinking...

: My Seiko, for example, does not have a COSC
: movement (naturally). The Seiko "breaks
: in" and accuracy "settles
: down" as the watch is worn.

: Now, the Omega has been tested and certified.
: This means the movement has more use time on
: the figurative odometer, doesn't it? So,
: will the Omega movemnt "settle" in
: or is what I see what I get? I'm expecting
: the latter, and expecting accuracy to
: decrease over time as the first service
: comes nearer. In contrast, the Seiko (and
: others) run a bit silly initially, then
: accuracy increases... before decreasing
: again as service time nears.

: Am I thinking about this correctly?

Actually, the COSC certification only describes how the movement performed during the test period and is not necessarily an indication of how it will perform once it is worn by the consumer. When COSC certification is completed, the movement is put into the watch where it may sit for months or sometimes years before it is purchased. So, by then, the movement will have been fitted into its case and worn by the user. The user's wear habits, overnight positioning, and other factors can contribute to the watch's "real world" accuracy. That's why the numbers on the COSC certificate really have only minimal value, since they reflect only values obtained on the "bare" movement in a controlled laboratory environment.

There's no way to predict whether your watch's timekeeping will change over a period of a few weeks or months, or whether it will run consistently from day one. I have Omegas that have exhibited both behaviors. Each and every mechanical watch is different, so you can't really predict how they will behave until you've worn them for at least a few weeks. You are correct, though, in that poor timekeeping is a definite indicator that it is time for a servicing.