How accurate is accurate?

The watch I'm wearing seems to keep pretty good time, but it's not perfect.

And can we all agree that internet derived time is functionally perfect? I don't know of any practical authority who considers internet (cell phone) time to be less than accurate.

I was re-reading the "Watch and Pocket Knife" thread on Friday, 27 May. I took my watch off and stopped it on the minute mark. I then watched my cell phone and did my best to sync time with it by closing the stem as the minute mark on my phone changed. I was close enough for any real purpose, in that my watch hit the minute mark approximately a half second behind the cell phone after the attempted sync.

Skip forward 9 days and there's another watch thread going. I checked my watch against the phone again, and danged if it isn't as close to exactly on as I can determine by simple observation.
Seems the watch has picked up a half second or so in the course of those 9 days.

A half second variance in 9 days looks pretty good to me, but how accurate can a wrist watch be?
What is the most accurate type of wrist watch, and what would you pay for that type of accuracy?

FWIW, the watch I'm wearing is a Bertucci classic titanium. About as reasonably priced as it gets...


"Chances Will Be Taken"