I grew up / went to school in the 70's and 80's. Every watch I had back then was quartz. I got my first mechanical watch in the mid 90's and haven't owned a quartz since. I've had Tag Heuer, Rolex, Tudor, Omega, Steinhart, Longines, and none of them have been as much as 10 seconds per day out, maybe I have been lucky.
This is the first vintage watch I have owned, but I thought that any movement can run fairly accurately if well serviced ?
My point wasn't if -10 seconds per day was good or bad for a 552 movement but whether this is classed as spot on which the seller claimed before purchase. It is only post purchase that the seller claims he knew it was losing time but thought it was 2-3 seconds per day, which I would have been over the moon with. My opinion is that 2-3 seconds could be classed as spot on, I wouldn't class 10 seconds per day as spot on.
I have never had a problem with a watch I have sold on here, but I did have a minor problem with a mobile phone I sold. I immediately offered the buyer a full refund and ended up agreeing on a partial refund to pay for the repair. I haven't asked the seller for a refund on this occasion as he basically doesn't want to know, he has the money, i don't even have his sympathy !
It looks like I will have to take it on the chin, the watch is a cool thing so I will probably just have to take it in to be checked out and serviced.
You live and learn