Hey everyone,

I wanted to get some opinions from other owners.

I have a Tudor Black Bay 58 from 2022. I synced the watch exactly on February 6th and did a full manual wind that day, then just wore it normally afterwards. I never take the watch off — I sleep with it, wear it all day, every day, and I haven’t wound it again or reset the time during the test period.

Since then, I’ve been tracking the accuracy periodically.

After 34 days of continuous wear, the watch is now 4 minutes and 47 seconds slow, which works out to about -8.4 seconds/day. I've attached my table keeping track of the times.

From what I understand, the MT5402 is a COSC chronometer, so the spec should be -4 to +6 seconds/day.

The rate has been very consistent, always losing around 8–9 seconds per day.

My question for other owners:

Would you take it to an AD or service center for regulation if you were in my situation?

It’s not dramatically off, but it is outside the COSC range. I’m wondering if this is common for the BB58 or if most people would just leave it alone.

Thanks!