Basically, I am never confident I am editing OSM correctly.
This is the case for the majority of users. The rules are complex and not always obvious or clearly defined. The world is complex, unfortunately, and so is describing it accurately.
One of OSM killer features for me is finding drinking water along the route when I'm hiking/biking/exploring. Unfortunately, there isn't a single, consistent label used for all sources of drinking water. So I have to check amenity=drinking_water, man_made=water_tap, amenity=fountain, one after the other.
I think StreetComplete has missions to add the label drinking_water=yes to all of those, so the situation might improve in the future.