While I only really care about a watch's accuracy to the point where I don't notice it being fast or slow this
link is a crucial aspect for mechanical watches and it's not 2007 anymore people aren't paying 110 for a
link 7S26-powered Seiko 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
link machine. This data is anecdotal to be sure but these are early examples that came directly from Seiko.