Recently, my watch broke. Well, kind of. I've never seen a watch break like this. Rather than the second hand moving 6Â° every second, every two seconds, it goes tick-tick and moves 12Â°, thus keeping perfect time. While on another errand to the local jeweler to see if they could fix my mother-in-law's earring, I casually showed it to the jeweler to see if she'd ever seen something like this. She explained, not very clearly (to me), that often watches have an auxiliary battery or chip or something that ticks every two seconds, and that when the battery runs low, it switches over to the two-second ticking.
Personally, I like the behavior. In fact, all other things being equal between two watches, I think I would actively choose to buy the one that does tick-tick every two seconds. If my local jeweler is correct, eventually it will stop completely, and then I'll seek help, but until then… Cool!