I’m someone who does that fairly frequently as needed.
My personal criteria are to do that when:
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I can identify the focus item as some kind of life vs say, a piece of plastic or a rock crystal, but can’t determine on my own what kingdom it could be among one or more. Algae (a couple kingdoms right there?) vs plants, slime mold vs fungus, living objects under microscopes, etc. A Life label is a handoff to someone with a better eye/more knowledge who can nudge it higher in the future.
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There are multiple possible foci potentially from different kingdoms and it may be hard to disambiguate (due to absent/unresponsive observer or whatever).
If there are site criteria that differ from those, someone please give me a heads up, thanks!