Okay so turns out my AirTags work fine on the second try in the wild.
Here's some stuff I learnt about how exactly they work:
- If location services and bluetooth are on, your iPhone will very frequently update the location of your AirTags in bluetooth range and it'll be highly accurate. So if you leave something behind by accident, even if no one else passes it, the last location it was seen by your phone will be shown and will be most likely correct.
- If location services is off on your phone, but your phone is in bluetooth range, no attempt is made by the AirTag to use the Find My network instead. The last location it logged from your iPhone is simply cached in the Find My app if "With You" shows up next to the AirTag.
- If you disable bluetooth so it no longer says "With You", but keep location services on, your AirTags begin using the Find My network including your iPhone. You can also turn location and bluetooth both off and it'll now be relying on other devices 100%.
- There is often (not always, but often) a 20-30 minute delay between location data being picked up by the Find My network and it showing up in the Find My app on your iPhone.
- Location is impressively accurate 90% of the time. If your item is indoors it isn't guaranteed to show the correct house number, or more likely the number will change when the location is updated and one might be correct but you won't know unless you already know which house it'd be in, but it will usually give you the correct street and generally the correct area within that street which is plenty good for a bluetooth tracker.
- If you leave an AirTag at home when you go out it'll start updating from the Find My network since your iPhone is out of bluetooth range.
So overall I am happy now I have a better idea of how they work. They do their stated job very well.
I'm also very impressed with the range, since an AirTag I left at home was having its location updated through the Find My network. Whether this happens for you will obviously depend on the location of the items, how close they are to the street, how many people walk or drive by your home, how big your house is, how thick the walls are, etc etc... but I didn't do anything special with the one I left at home, I kept it where I normally do, not right up by the window or anything.
I do wish the AirTags would update from the Find My network if I disable location services but keep bluetooth on from my iPhone, but I'm guessing that's a battery saving feature and Apple is assuming most people using these will always have location services enabled.
Just a shame there's no support for the Find My network on my S6 Apple Watch especially as it has the U1 chip. I hope that gets added in a near future software update.
Either way - the Find My network clearly does its job, the number of times various iDevices pinged my AirTags in various locations was impressive and provided reliable data most of the time, and they do exactly what I expected from bluetooth based trackers. I'm pretty confident these would help me locate lost items.
P.S. Protip: do NOT put AirTags in those net things on the front of bags, for example like the net on the Sony WH-1000XM4 carry case. They will easily fall out. Put them inside somewhere instead.