I thought it was time to share my experiences with using sleep tracking apps on my Apple Watch.
Not long after posting the question I downloaded Sleep++ and used that for quite a while. Sleep++ works well. It is power efficient and met most of my requirements. It's not perfect (e.g. you need to manually start/stop sleep tracking, but it's free (with ads - but the ads don't appear on the Watch) so you can give it a good try before paying to remove ads. It's also very well supported by the developer.
My hope was to use this app until Apple's own implementation of a sleep tracking app in watchOS was released. But since this wasn't ready in time for watchOS 4, and since I upgraded to a new Series 3 Apple Watch, I decided it was time to look at another sleep tracking app - namely one that doesn't require me to manually start and stop it (for those times I forgot, or those times I dozed off unintentionally).
I settled on AutoSleep which is a paid app. I've been using it for a couple of weeks and have been very impressed with how well it works and how it meets all my requirements.
It can automatically detect your sleep (assuming you're wearing the watch) or you can use it manually (similar to Sleep++ but without having to wear the watch). Obviously using it manually is not going to provide all the measurements, but it's equivalent to what Sleep++ could do.
Also, if you're wearing the watch, you can manually enable the Lights Off option. This is not necessary, and since one of the best selling points of this app is that it automatically detects your sleep without manual intervention, you may not want to opt for this. But if you do, it tells the app that you've officially gone to bed (hence the 'lights off' label) and the app will also track how long it takes you to fall asleep after going to bed. Useful if you want to also track that metric.
One of the other great features of the app is that on the iPhone you can tweak it to suit your sleep. That is, the app provides some nice measurements and graphs to illustrate your sleep and, if you notice it hasn't detected your sleep accurately enough (e.g. you know you woke up during the night and the app hasn't detected that), you can alter how sensitive it is or isn't to tracking your sleep. For me, I've never had to tweak it. It has accurately recognised my start sleep time, as well as my restlessness and any time awake in bed during the night. It has also detected times that I've dozed off in front of Netflix, while reading a book, etc regardless of the time of day!
All in all I am very happy with this app and it's very close to how I imagine Apple will implement its own version.
As there is no free version available, feel free to ask me any questions about this app in the comments below.
NOTE: I am not affiliated with this app in any way.
You'll need to set up the iOS version of Keynote on your iPhone to be a remote control for Keynote on either another iOS device (such as your iPad) or your Mac. To do this, perform the following steps:
On the device that you'll be using to present from, open the remote control configuration:
On iOS, this feature is located in Remote | Devices | Add a Device
On OS X, this feature is located in Keynote | Preferences | Remotes (Ensure that the Enable checkbox is checked)
On the iPhone paired with the Apple Watch, open Keynote and select Remote | Devices | Add a Device
On the Mac or iOS device you'll be presenting from, select the Link button beside the remote device that you wish to use to control presentations
Verify the code shown on the screen, then complete the setup
Once this initial setup has been completed, open the Keynote app on your presenting device and begin a presentation.
On the Apple Watch, launch the Keynote app. Once the app launches, it will search and connect to the paired Mac or iOS device used for presentations. You'll get a Ready message (Figure A) when you're ready to control a presentation. When you see this message, it means that you can open the presentation on your Mac or iOS device that you'll be presenting.
http://www.techrepublic.com/article/pro-tip-how-to-use-the-apple-watch-to-control-keynote-presentations/
Best Answer
TLDR - Could Apple do this with a quick update - of course it’s technically possible. Will Apple do so? I prefer the odds a snowball survives in December in Australia, but who knows what new hardware will allow or if software in the future is allowed to spend watch battery on this feature.
On a technical level, with the current iOS/iPadOS/watchOS throttling background data connections at 30 seconds in general when it used to be 10 minutes, there is no way you’ll be able to fit that much data through the watch hardware. My opinion is the carriers are borderline cruel to even offer that much “watch data” in my opinion let alone charge you $120 per year plus fees for that premium data. It would be a triumph to exhaust that data cap with the hardware and software going into 2020.
You are correct that if the watch is on WiFi - it will tunnel all data over that and if that doesn’t work, then the watch will talk to your iPhone over bluetooth to avoid running the LTE on the watch.
WatchOS will only consume cellular as the last resort and certainly the tethering code is disabled on watchOS as well to save power and allow it to run as described above.
If cost savings is your desire, consider dropping LTE on the watch and seeing if you an manage without it and fund more phone data.