Apple Watch Se Vs Series 9 Do You Really Need The Always On Display And Blood Oxygen Sensors

The Apple Watch lineup offers a range of options, each tailored to different needs and budgets. At first glance, the Apple Watch SE and Series 9 appear similar—same circular design, shared fitness tracking features, and seamless integration with the iPhone. But dig deeper, and the differences become clear. The Series 9 includes premium features like an Always-On Retina display and blood oxygen (SpO2) monitoring, while the SE skips these to keep costs down. So, is the upgrade worth it? For most users, the answer depends not on what the technology can do, but on how much they’ll actually use it.

Design and Core Features: More Alike Than Different

Both the Apple Watch SE (2nd generation) and Series 9 share Apple’s signature aluminum case, digital crown, and side button layout. They run the same operating system—watchOS—and support identical core functionalities: heart rate monitoring, ECG readings (on GPS + Cellular models), sleep tracking, fall detection, and emergency SOS. Both are water-resistant up to 50 meters and offer comparable battery life—about 18 hours under normal use.

Their displays differ in technology, not size. The Series 9 uses an LTPO OLED panel that enables the Always-On Display (AOD), meaning the screen remains dimly lit even when your wrist is down. In contrast, the SE uses a standard OLED that turns off completely unless activated by raising your wrist or pressing a button.

This distinction affects convenience more than functionality. With the Series 9, you can glance at the time, notifications, or workout stats without moving your arm. For some—especially those frequently checking data during workouts or in meetings—this is a meaningful advantage. For others, it may simply mean slightly faster battery drain.

Tip: If you're often in situations where discreet glances matter—like presentations or quiet environments—the Always-On Display can reduce the need for obvious wrist movements.

Always-On Display: Convenience vs. Practicality

The Always-On Display on the Series 9 dims to 1% brightness when your wrist is down, preserving battery while keeping essential information visible. It adjusts dynamically based on ambient light and motion, brightening when you look directly at it thanks to the built-in ambient light and motion sensors.

But does this feature justify the price gap? For active professionals, parents managing schedules, or fitness enthusiasts tracking real-time metrics, yes—it adds subtle but consistent value. You no longer have to interrupt your flow to check elapsed time during a run or confirm a notification mid-conversation.

However, if you're someone who checks your watch infrequently or primarily uses it for notifications and health alerts, the SE’s traditional screen behavior may be perfectly adequate. Turning the screen on requires only a slight wrist tilt—an action most users perform instinctively.

“Always-On Display isn’t about necessity; it’s about reducing friction in daily interactions with your device.” — Dr. Lena Park, Human-Computer Interaction Researcher, Stanford University

Blood Oxygen Monitoring: Useful Tool or Underused Feature?

The Series 9 includes a blood oxygen sensor, allowing users to measure SpO2 levels—a metric indicating how well oxygen is being delivered to parts of your body. This feature gained attention during the pandemic as a potential early warning sign for respiratory issues. Apple markets it as part of its broader health ecosystem, especially useful for detecting trends over time.

In practice, though, most users rarely engage with this function. Unlike heart rate, which runs continuously in the background, blood oxygen readings require manual initiation through the Health app. Even scheduled background measurements occur only during sleep and aren't designed for real-time medical diagnosis.

Clinically, SpO2 monitoring matters most for individuals with chronic respiratory conditions like COPD, asthma, or sleep apnea. For them, spotting downward trends in overnight oxygen saturation can prompt earlier consultations with doctors. But for the average healthy user, these readings often remain within the normal 95–100% range, offering little actionable insight.

That said, having access to this data creates peace of mind. Knowing you *can* take a reading during illness or high-altitude travel adds a layer of preparedness—even if used sparingly.

When Blood Oxygen Sensing Adds Real Value

• Monitoring recovery from respiratory infections like bronchitis or pneumonia
• Tracking sleep quality in suspected sleep apnea cases (in conjunction with other diagnostics)
• Hiking or traveling at high altitudes where oxygen levels drop
• Supporting telehealth check-ins with physicians who request periodic SpO2 logs

Tip: Enable overnight blood oxygen tracking in the Health app settings to gather passive data without daily effort.

Detailed Comparison: Apple Watch SE vs Series 9

Feature	Apple Watch SE (2nd Gen)	Apple Watch Series 9
Display	OLED, non-Always-On	LTPO OLED, Always-On Retina Display
Blood Oxygen (SpO2) Sensor	No	Yes
ECG App	GPS + Cellular model only	All models
Processor	S8 SiP (similar to Series 8)	S9 SiP (faster, more efficient)
Double Tap Gesture	No	Yes (new feature using S9 chip)
Ultra Wideband Chip (U2)	No	Yes (improves Find My precision)
Price (Starting, GPS Model)	$249	$399
Customization & Watch Faces	Full support	Same, plus enhanced face personalization via Double Tap

The table highlights that beyond the two headline omissions—Always-On Display and SpO2 sensing—the SE lacks several newer capabilities powered by the S9 chip. These include the “Double Tap” gesture control (pinching fingers twice to answer calls or dismiss alarms) and improved location accuracy via U2 chip integration. While not game-changers, they represent incremental quality-of-life improvements that enhance usability.

Real-World Example: Two Users, Two Choices

Consider Sarah, a 34-year-old project manager and mother of two. She uses her Apple Watch mainly for calendar alerts, step counting, and receiving messages during school pickups. She values simplicity and doesn’t want unnecessary complexity. After testing both models in-store, she chose the SE. “I don’t need the screen always on,” she says. “And I’ve never once taken a blood oxygen reading on my old watch. For $150 less, I got everything I actually use.”

Then there’s James, a 42-year-old endurance runner with mild asthma. He trains six days a week and tracks his recovery closely. He upgraded to the Series 9 specifically for the Always-On Display—he finds it invaluable during long runs when he doesn’t want to lift his arm constantly. He also reviews his overnight SpO2 trends monthly and noticed a dip after a chest infection last winter, prompting him to schedule a doctor’s visit sooner than he might have otherwise.

Their experiences underscore a key truth: the right choice depends on lifestyle, not just specs.

Checklist: Should You Upgrade to Series 9?

Answer the following before deciding:

1. Do you frequently check your watch without wanting to move your wrist? → Always-On Display benefits you.
2. Are you managing a respiratory condition or regularly train at altitude? → SpO2 monitoring could provide valuable insights.
3. Do you value cutting-edge interaction methods like Double Tap gestures? → Only available on Series 9.
4. Is precise location tracking important (e.g., finding your watch near other devices)? → U2 chip gives better accuracy.
5. Would saving $150+ make a noticeable difference in your budget? → The SE delivers excellent value.

If three or more answers lean toward \"yes\" for advanced features, the Series 9 makes sense. Otherwise, the SE likely covers your actual needs.

Frequently Asked Questions

Can the Apple Watch SE get software updates as long as the Series 9?

Yes. Both watches run the latest version of watchOS and will receive updates for several years. Apple typically supports devices for 5–6 years, so both models will stay current well into the future.

Is the heart rate accuracy different between SE and Series 9?

No. Both use the same third-generation optical heart sensor and deliver clinically reliable heart rate data under normal conditions. Differences arise only in additional metrics like blood oxygen, not core vitals.

Does the Always-On Display drastically reduce battery life?

Apple claims minimal impact due to aggressive power optimization. In real-world tests, the Series 9 lasts about 16–18 hours with typical use, compared to 17–19 for the SE—a difference of roughly one hour. For most, this trade-off is acceptable given the convenience.

Making the Right Decision for Your Lifestyle

The Apple Watch SE remains one of the best smartwatches for everyday users. It includes nearly all the health and safety features people rely on—fall detection, emergency SOS, irregular rhythm notifications, and robust fitness tracking—at a significantly lower price point. Unless you’re drawn to specific Series 9 innovations, the SE delivers exceptional performance without compromise.

The Series 9, meanwhile, refines the premium experience. Its Always-On Display enhances readability in fast-paced environments, and its blood oxygen sensor adds a dimension of proactive health awareness. Combined with the new S9 chip’s efficiency and gesture controls, it represents the current peak of Apple’s wearable tech.

Ultimately, needing these features isn’t the same as wanting them. Many buyers are influenced by marketing language around “advanced health monitoring” or “seamless visibility,” but true utility lies in consistent usage. Ask yourself: Will I use this weekly? Monthly? Or will it sit unused, a technical checkbox with little real-world impact?

Conclusion: Choose Based on Use, Not Hype

The gap between the Apple Watch SE and Series 9 isn’t about capability—it’s about refinement. The SE handles core functions flawlessly. The Series 9 polishes the edges with convenience-driven upgrades. Whether you need the Always-On Display or blood oxygen sensors depends entirely on your habits, health priorities, and daily routines.

If you're buying your first Apple Watch or replacing an older model without urgent health monitoring needs, the SE is the smarter financial decision. But if you're already deep in the Apple ecosystem, prioritize seamless interaction, or manage a condition where oxygen trends matter, the Series 9 earns its premium.

🚀 Ready to choose wisely? Assess your real usage patterns—not just the brochure specs—and pick the watch that fits your life, not just your wishlist.