Daylight saving time ends in the US this Sunday. Somewhere in the region of a hundred million people own a Casio F-91W or one of its descendants, and a good number of them will spend part of Sunday morning holding down a tiny button, cycling past the minutes, and getting the hour back where it belongs.

The Casio F-B100W is the first watch in this shape that handles that for you. It's $64.95, it counts your steps, and it looks almost exactly like the watch Casio has been making since 1989.

What the Casio F-B100W Adds

Casio has kept the silhouette and added two genuinely useful things.

Step Tracking

There's a motion sensor in there now. It counts steps up to 999,999, draws an hourly activity graph right on the display, lets you set a daily target, and nudges you when you've been sitting still too long. Casio calls the broader data set a life log.

That's not a fitness platform and it isn't trying to be. There's no heart rate, no GPS, no sleep scoring, no app subscription waiting at the end of a free trial. It counts your steps and shows you the shape of your day. For a very large number of people, that is the entire amount of fitness tracking they actually use.

Bluetooth

The watch pairs to the Casio Watches app, and this is the part that quietly matters more.

Automatic time adjustment means the watch sets itself and stays set, including through the clock change this weekend. Easy watch setting means you configure alarms and settings on your phone screen instead of button-cycling through menus, which anyone who has ever set a vintage Casio alarm will appreciate immediately. You also get roughly 300 world time cities, a time and place log, and a phone finder.

Worth noting: even unpaired, the module 3589 is rated at ±15 seconds per month. The F-91W's module 593 is rated at ±30. So the new watch is twice as accurate before Bluetooth does anything at all.

The rest of the feature set is classic Casio: dual time, full auto-calendar, five daily alarms, hourly signal, a 1/100-second stopwatch running to 60 minutes with 200 stored records, a 30-minute countdown timer, and a green LED backlight with selectable 1.5 or 3 second duration.

The Battery Trade, Honestly

Here's the one real cost, and it deserves a straight answer rather than burying.

The F-91W runs about seven years on a single CR2016 cell. The F-B100W runs about two years on the same cell. A Bluetooth radio and a motion sensor have to draw their power from somewhere, and that's where it comes from.

Seven years is a genuinely remarkable number and part of why the F-91W is beloved. Two years is a significant reduction from it.

Two years is also still an extraordinary figure by any modern standard. A smartwatch asks for a charge every day or two. A fitness band might stretch to a week or ten days. The F-B100W asks for a coin cell roughly once every two years, and otherwise never asks you for anything. Measured against the thing it's actually replacing, that's a different category of convenience.

F-B100W vs F-91W: What's Actually Different?

Put the F-B100W next to the F-91W and the family resemblance is obvious. The newer watch is larger, though only slightly: 41.9 x 38.1 x 8.8mm compared with 37.5 x 34.5 x 8.5mm for the F-91W. Weight moves from 21 grams to 26. In other words, Casio found room for Bluetooth and a motion sensor without turning this into a bulky digital watch.

The bigger differences are inside.

• Accuracy: The F-B100W's module 3589 is rated to ±15 seconds per month, compared with ±30 seconds per month for the F-91W's module 593.

• Battery life: Both use a CR2016 battery, but the F-B100W is rated for roughly two years while the F-91W stretches to about seven.

• Step tracking: The F-B100W counts steps and records activity. The F-91W does not.

• Bluetooth: The F-B100W connects to the Casio Watches app for automatic time adjustment, easier settings, world time functions and phone finding.

• Water resistance: The F-91W carries a 30-meter rating. Casio lists the F-B100W under its basic water-resistant designation, making it suitable for everyday splashes and rain rather than swimming.

• Price: The F-B100W is $64.95, while the F-91W typically sits around the $20 mark.

That makes the trade pretty easy to understand. The F-91W remains smaller, cheaper and dramatically better on battery life. The F-B100W gives up some of that simplicity in exchange for automatic time correction, step tracking and a much easier way to manage its settings.

For something carrying extra electronics, the physical penalty is tiny. Five grams and a few millimetres are unlikely to change how the watch feels in daily use, and at 26 grams it is still the kind of watch you can forget is on your wrist.

Three versions are available: the FB100W-1A in black with a blue display ring, the FB100W-1B in black with an inverted LCD, and the FB100W-3A in green. The inverted LCD joined the US lineup after the initial announcement.

One practical detail deserves extra attention if you already own an F-91W. Its 30-meter water-resistance rating gives it more reassurance around water than the F-B100W's basic water-resistant designation. If swimming with your old Casio has become second nature, the newer model calls for a little more restraint.

What It's Actually Competing With

The instinct is to line this up against the F-91W and ask whether it's worth five years of battery life. That's the wrong comparison.

The F-91W still exists, still costs about twenty dollars, and still does its job perfectly. Nobody at Casio is asking you to retire one. If what you want is a watch you put on and forget until the next presidential administration, that watch remains in production and remains excellent.

The F-B100W is aimed at a different person: someone who would quite like to know roughly how much they walked, who has looked at the smartwatch aisle, and who has concluded that charging a wrist computer every night and paying a monthly fee to read their own step count is more than they signed up for.

For that person, $65 buys a sensor, a Bluetooth sync, a two-year battery, and complete silence otherwise. No notifications. No upgrade prompts. No subscription. Casio tried a version of this idea before with the steel ABL-100 at $95, a more sophisticated watch, but putting it in the F-91W body at $65 is what makes it land.

Where It Lands

There's something quietly confident about Casio's approach here. The F-91W was designed in 1989 by Ryūsuke Moriai as his first project for the company, and roughly 100 million examples later it remains the best-selling watch in the world. A design with that track record is not one you touch casually.

Casio touched it carefully. Same look, same proportions give or take a few millimetres, same resin construction, same basic promise. Two features added, one trade made, price kept under seventy dollars.

That's a sensible piece of product design, and it fills a gap that had been sitting open for years between the traditional digital watch that lasts forever and the smartwatch that needs feeding nightly.

Affordable watches that do exactly what they claim and nothing else are the backbone of this hobby, and they're most people's way into it, which is the thinking behind a lot of what we stock across the Watch Gang store. The same logic runs through every membership box we put together.

Set your clocks Sunday. Or buy the one that does it for you.