While I only really care about a watch's accuracy to the point where I don't notice it being
link fast or slow this is a crucial aspect
link for mechanical watches and it's not 2007 anymore people aren't paying 110 for a 7S26-powered Seiko
link that keeps iffy time. As such while neither the SPB453 nor 451 triggered my own mental accuracy threshold I did put both of them on a timing machine. This data is anecdotal to be sure but these are early examples that came directly from Seiko.