Forerunner 645 for health purposes only

I’m not saying you need a rational reason to spend lots of money on a gadget - but I don’t understand why you spend that kind of money on a Fenix when clearly its features are not what you want/urge/desire. It sounds strange to me to spend $1000 and not even bother to find out what features are in there.

I certainly don’t NEED all the features on my Fenix, but my irrational reason for buying it was that I WANT the fancy features and have found them quite useful after some use.

So to sum it up:
You have bought a Fenix for reasons that you consider irrational, and you don't understand why I would buy a Fenix for irrational reasons.

I rest my case.

Okay, I won’t drag out the discussion, my point simply was that the difference is that I chose to spend the money on features I wanted, and you spent the money on features you didn’t wanted.

SAHO I appreciated the time you are taking to help me! So do you think that those stats are precise enough to be useful and can't easily be seen from somewhere else?(maybe connecting to different app or something)

I think that the stats are precise enough - given that the watch is fed with good data. By that I mean that it might need you to wear a chest strap for accurate HR (see loads of other threads on wrist sensor accuracy) and maybe even a foot pod for accurate pace/distance when running, or cadence/speed/power sensors while cycling. (not really sure what's needed to get full benefit for cycling as I don't cycle myself.)
That said; I think the extra stats will guide you in the right direction whether you use additional sensors or not, and the beauty of a higher end device is that you can choose to expand your "system" as you get more serious instead of needing to buy a whole new device.

The VA3 will give you VO2max estimate (at least for outside running), but on watches including training status, VO2max is only one of the metrics that goes into the equation. In example: fitness (VO2max) might decrease even if your load goes up, which means your overreaching.
On the VA3 you would only see your VO2max decrease, but on the 645 could also get the information why it's decreasing. Getting information on aerob/anaerob training effect is also very helpful in this context.

Okay, I won’t drag out the discussion, my point simply was that the difference is that I chose to spend the money on features I wanted, and you spent the money on features you didn’t wanted.

I think you should read more carefully before you make any statements about my purchasing decision.

You seem to assume that I only wanted the Active Calories count and no other functionality when I bought my watches. If you read more carefully, I have written absolutely nothing which can be interpreted that way.

In fact, I had a whole number of requirements when I bought my first Fenix. And to make your wrong assumption look even more silly: The Active Calories count was not among those requirements. It took more than a year before I started paying any attention to that metric.

I can see that my new 5X+ has something called Training Load. I guess that is another way of keeping track of one's general activity level. But I think I will stick to my Active Calories for now

I'm sorry if I misinterpreted you. The statement quoted above was the one that threw me off, and together with the statement that the calories estimate to you is the most vital feature on your Fenix gave me the impression that you are not interested in any of the advanced training metrics/analysis that you have paid quite a lot of money to get.

Blizz I'm sorry, it was not my intention to hijack your thread with the (kind of) off-topic argument back and forth with AllanOlesen67

It depends what you mean by health. Do you care about how your body looks? How you feel? How long you live? Being able to run fast and far lift a lot is very important to me, even though I do few, if any, competitive actives - does performance matter to you?

Training Status, Training Load, Training effect and % HRR Recovery Time are all things that make the price of the watch well worth it to me. But this is more about how you train than what you train for. If I do a recovery run, I go for a TE of 2, and a hard run I go for a TE 4. But someone else may prefer time or distance goals.

If Auto max HR means the watch sets your max HR for you, I don't find this useful or accurate. Max HR changes rarely and is hard to get a good estimate of. I rarely go above 180, but measured 221, so I wouldn't be surprised if my Max HR was anywhere in that range. I set it so I get useful zones and TE.

At least for me, the price difference between a Vivoactive 3 and a used 645M is negligible, compared to the commitment of wearing it 24/7, learning how it works and how to use it, and basing my training plans around the watch. I will have this watch for years and sell it when I upgrade. So the Vivoactive would probably save less than 10 cents per day. That doesn't matter to me, but it might for some people.

So I can mix a variety of activities and still keep easy track of my weekly goal of 4200 Active Calories.

Thanks for highlighting this, it is really interesting. Is there someplace that the weekly total of active calories is shown? I can only find the average over the past 7 days in Garmin Connect (which is good enough to determine above/below 4200).