Why Changing the Date Can Break Your Watch

Okay so this is one of those things that every watch person knows but nobody ever properly explains to beginners, and it leads to a lot of very expensive mistakes.

Your mechanical watch has a danger zone. Usually somewhere between 9pm and 3am on the dial. Change the date during those hours and you might hear a noise you really don't want to hear. Or worse, you won't hear anything at all but you've just bent something inside that's going to cost you a few hundred pound to fix.

Here's what's actually happening in there. The date change doesn't just snap over at midnight like magic. There's a whole mechanism that starts engaging hours before. Little levers and wheels slowly building up tension, getting ready to push that date disc forward. When you're in that window, those parts are already meshed together, doing their thing, under tension.

Now you come along and try to quick-set the date using the crown. You're essentially forcing the mechanism to move in a way it wasn't designed to while it's already halfway through its job. Things that should move freely are locked in position. Things that should be locked are being forced to move. Metal bends. Teeth on wheels can strip. Levers can snap.

And the annoying thing is it might not break immediately. Sometimes it'll work fine for a few weeks and then suddenly your date stops changing altogether, or it starts changing at 4pm, or it gets stuck between two numbers. By then you've forgotten all about that one time you set the date at 11pm and you're wondering why your perfectly good watch has decided to pack it in.

The fix is stupidly simple: before you touch the date, wind the hands forward past 12 until you see the date change. Now you know you're in the safe zone - sometime in the early morning. Set your date to yesterday's date, then wind the hands forward to the correct time. Done. Takes an extra thirty seconds and saves you a service bill.

Some modern movements have built-in protection against this. They'll have a clutch system or the quick-set is designed to disengage when the mechanism is active. But unless you know for certain your specific movement has this feature, just assume it doesn't. It's not worth the risk.

The really paranoid among us (myself included sometimes) just never use the quick-set date function at all. Wind the hands forward, let it change naturally, set the time. Takes a bit longer if your watch has been sitting for a while and you're three weeks behind, but there's literally zero chance of damaging anything.

One more thing - this applies to day-date complications too. Same principle, sometimes even more delicate because you've got two discs and more wheels involved. And perpetual calendars? Don't even think about touching those without reading the manual first. Those things have so many levers and cams working together that you really need to know exactly what you're doing.

So yeah. Stay out of the danger zone. Your watchmaker will thank you.