Graham,
This is what I want to know more about.
I don't think I have any special needs as regards smart folders, they all seem to work the same way, and I've not really thought about it in any detail, just used them.
However, I now realise my term "nested" is misleading as the nesting comes from container/collection folders rather than the nesting of saved search/filtered smart folders. Sorry if this was confusing.
I assume we are using "smart folder" to mean the same thing ie a a folder that has an associated search or filter that runs when you open the folder so it updates the folder contents every time its opened. And all the programs search tools are available when setting up the search criterion for the folder.
As regards my earlier example, it should read:
Woodlands (container folder)
>Woodland 2020 (container folder)
>Spring woodland 2020 (smart folder with saved search or filter)
>Summer woodland 2020 (smart folder with saved search or filter)
>Autumn woodland 2020 (smart folder with saved search or filter)
>Winter woodland 2020 (smart folder with saved search or filter)
>Woodland 2021 (container)
>Spring woodland 2021 (smart folder with saved search or filter)
>Summer woodland 2021 (smart folder with saved search or filter)
>Autumn woodland 2021 (smart folder with saved search or filter)
>Winter woodland 2021 (smart folder with saved search or filter)
Is there anything more specific you want?
No, I think I'm on the same page as you, just as long as you don't mind them being called "Smart Collections" instead of "Smart Folders".
-Kirk