The Apple Watch Series 10 is the smartwatch most people should buy | CNN Underscored

It’s comforting to watch Apple iterate on its basic watch design year after year. You can always count on a new Series-whatever watch, a new SE and, for the past two years, a new Apple Watch Ultra. It was reliable, predictable, a calm port in a storm of technological and chronometric uncertainty.

This year, not so much. Apple tricked us all with no updates to the entry-level Apple Watch SE, and the Ultra 2 got a paint job. (It’s black. End of story … almost.)

But the new Series 10 may make up for all that. It’s a slim, sleek and light smartwatch that does 95% of what the Ultra does for a fraction of the weight and price. Add an improved, bigger screen, and you may have the new best smartwatch for most people. It’s that good.

Let’s start with the most obvious: the design of this thing. Apple says it’s almost 10% thinner than the Series 7, 8 and 9 while offering a much bigger screen and an 18-hour battery life. Apple accomplished this with a thinner chipset that uses as little battery as possible and some new manufacturing processes that integrate the antenna and the watch housing, combining the two layers.

The wide-angle OLED display makes the display big and bright. Apple says it’s 40% brighter than a Series 9 when viewed from an angle. I couldn’t test it against a Series 9, but it easily outshone even the Ultra 2, which has one of the brightest screens of any smartwatch.

And its screen is physically big, too. Available in both 42mm and 46mm sizes, it’s a long way from the original Apple Watch, which was a puny 38mm and 42mm. The display area of the larger Series 10, at 1220 sq mm, is even larger than the Ultra 2 (1185 sq mm), even though the new watch is physically smaller.

What’s a bit remarkable about this is that it doesn’t feel large on my wrist. Nor does it look huge. I have an average-sized wrist, so this was never much of a problem for me, but for the thin-wristers out there, the Series 10 won’t overwhelm.

And with its slimmer profile, the Series 10 doesn’t catch on your cuff and weighs so little you’ll likely forget you’re wearing it. It clocks in at 1.25 ounces for the 46mm GPS + Cellular Aluminum model and just over 1 ounce for the 42mm GPS + Cellular. Compared to the Series 9, which has a smaller screen, it’s about 0.13 ounces and 0.1 ounces lighter. And just to throw the Ultra 2 into the mix, Apple’s higher-end watch weighs a beefy 2.2 ounces with a 49mm screen. You can’t forget that you’re wearing the Ultra 2.

The Series 10 is offered in GPS and GPS + Cellular models and comes in jet black, rose gold and silver for the aluminum models and slate, gold and natural titanium.

And remember that 18-hour battery life I mentioned? It’s the real deal. A slimmer, lighter watch with a bigger screen would usually translate into a loss in battery life. (There isn’t as much space for a larger battery; the screen would use more power, etc.) But in this case, Apple has managed to eke out more efficiency and kept the 18-hour life of the Series 9. In my experience, it tracks pretty closely with what’s advertised and then some. I often use it for sleep tracking and wake up with 80% or more battery life remaining. Apple also has a low-power mode that it says will last 36 hours, but I didn’t have a chance to test that out.

The Ultra 2 is still the champ of battery life, however, with 36 hours of normal battery and 72 hours of low-power mode.

Of course, you get all the usual functions of the Apple Watch line, such as heart rate monitoring, crash and fall detection, workout tracking and the like. But the zippy Series 10 really lets the newest features of watchOS 11 shine. The new Smart Stack, which puts the most essential information you need right now — as near as the onboard machine learning can determine — is big and easy to tap through. The watch’s double-tap feature, introduced last year,  is fast and accurate and lets you tap your forefinger and thumb together to scroll through an app’s information while interacting with the watch with one hand.

Sleep tracking is a delight. Given the watch’s slim profile and small weight, it’s great for wearing as a sleep tracker. I used to use the Ultra 2 for this, but it was big and bulky and more than once, I woke myself up by knocking it against the headboard. WatchOS 11 also brings sleep apnea notifications.

Sleep apnea, a condition in which sleepers stop breathing for up to 30 seconds many times a night, is a serious and underdiagnosed medical condition. Some 936 million people around the world, including 39 million Americans, are estimated to have some form of this condition. It can lead to myriad health complications, including hypertension, type 2 diabetes, an increased risk of strokes, depression and memory issues. But only about 6 million Americans have been diagnosed and get treatment. I am one of them.

Apple says that it relied on some 11,000 nights of sleep study data spanning a wide range of demographics to develop the new technology, which is only available on the Series 9, 10 and Apple Watch Ultra 2. It doesn’t rely on blood oxygen readings, a function unavailable in the United States thanks to a patent dispute with Masimo. Instead, Apple says, it uses the watch’s insanely sensitive accelerometer to detect the rising and falling of your chest as you sleep. Over about 30 nights, it builds up a picture of whatever “breathing disturbances” you might have and sends a notification to your phone if it appears you have a spike in disturbances. This doesn’t diagnose sleep apnea, nor does it take the place of a dedicated sleep study. Apple is very clear about that. But it gives people the nudge to talk to their doctors and get proper treatment if needed.

Rounding out the improvements over the Series 9 are a depth gauge down to 6 meters (19.7 feet) and a water temperature sensor. This is fine for snorkeling but not scuba, which is still the exclusive domain of the Ultra 2.

There was only one thing to dislike: the lack of a blood oxygen sensor. But honestly, you probably won’t miss it. When I asked about whether there was any development in resolving the patent dispute, Apple reps were firm in saying only that the Series 10 and Ultra 2 sold in the United States would not have the sensor. However, given that the sensor is available on watches sold outside the United States, it seems a given that once the dispute is resolved, a software update will turn the O2 sensor back on.

For those hoping for new features on the next generation of Ultra watches, I hope you like black. Because that’s the sum total of the changes in the Ultra line. It looks very handsome, like a Batwatch; but if you’re wondering if you should upgrade to the Ultra 2, I’d refer you to our review from 2023 that outlined who should consider upgrading.

Here’s the deal: As good as this watch is, you might not need to upgrade from the Series 9, which is already great. The Series 10 is thinner and lighter, offers a brighter screen, and has better snorkeling support with the Oceanic+ app. However, with watchOS 11, the Series 9 gets the sleep apnea, double-tap, vitals app and almost all of the other functions of the Series 10 and Ultra 2.

If you’re looking to move on from a Series 8 or earlier, the case for upgrading is more compelling. You get low-power mode for up to 36 hours of battery life, sleep apnea notifications, as well as a much better display.

The real question to ponder is whether the Series 10 is a worthy alternative to the Ultra 2. Do you scuba? Then the Ultra 2 is the one for you. But if you don’t, the Series 10 will do almost everything else the Ultra 2 does, minus the rugged construction and the extra cost. I’m a diver, so I’ll stick with the Ultra 2, but I’ll definitely be using the Series 10 for those occasions when I don’t want or need a big chunky watch on my wrist.