So, no more than days away from having been raving about how exceptional, beautiful and otherwise brilliant my Navi 01 was, I'm in with a problem. Actually, it was already in the making then, I just didn't know about it.

Out of nowhere, literally out of nowhere, my Navi has decided that every day had 10 superfluous seconds with could be dismissed and certainly didn't need any keeping track of. So it from its so far steady 2 seconds a week to a rather shocking 10 seconds a day. I noticed when suddenly, it was a minute later on my watch than on my phone... Not a good sign I thought, set it again at exactly midnight this very early morning. On lunch today, it was 5 seconds fast.

So of it went to the AD and from there to the factory...

I'm rather sad I had to send it off to days before the first anniversary of me first picking it up. I suppose it had a wellness weekend (more like a month really) at the spa on top of its Bday wish list... Anyhow, well take that as an opportunity to see how good customer service is here in the land of the ling.

I'll keep you posted.

10 sec off per day is a common issue for B01, IMO either yr watch's amplitude is low and needs a little servicing or it just needs some regulation and should be fine. I sent in mine early last mth and got it back after about a week plus. So far has been working perfectly fine after getting my baby back. The customer service here is marvelous. I saw a hairline scratch on the side of the lug after getting my watch back, I wasn't sure if it had been there in the first place but when I told the staff that it wasn't done by me, they had the portion polished and scratch removed on the spot. To my delight the most obvious scratch on my watch happened to be on the same area and was removed as well. I expect the customer service in Switzerland to be even better? My suggestion is to let yr chronograph run for 12 hours after getting yr watch back to check for any other faults. U got 5 years to perfect yr Nav01 so make full use of it;)

Both my Chronomat 01 and Navi 01 experienced the same sudden issue about 2 months ago. My Chronomat has been plagued with issues since day 1, so I just chalked it up to this. However, my Navi has exhibited no real issues, so I was surprised to see it go from +1 sec/day to +11. I'm basically convinced these movements are bound to be problematic and will wait to send them in until they need a routine service. No more in-house Breitling movements for me.

My new b01 is anywhere from +1 to -2 seconds/day. It seems to be on the negative side if it is not worn all day. This is different from others here who have stated that at the end of the reserve, their watch runs faster.

Bigger issue is what caused it to suddenly happen? Would a low amplitude cause a watch to run fast, sure, but tough to imagine what would cause a watch to suddenly have a low amplitude - that's more a gradual wear and tear issue as the hairspring wears out. Dirt / contamination will usually result in increased friction and therefore slow the watch down, but really it's pure guess work. A regulation will likely solve the problem if the error is a consistent 10 seconds a day (it's realtively easy to regulate for a consistent error), but my concern would be whether the underlying cause of the problem had been addressed or whether there is a problem waiting to come back.

What seems stranger is that my Evolution actually keeps more accurate time than my b01. I use my cell phone minute change as the guide.