how I learned to "know".
with a fresh chain on a fresh chainring installed on a bike, pull radially outward from one link pin in the middle of the chain engagement with the chainring. Note the very slight displacement.
Now with a fresh chain on your worn chainring while mounted on the bike, do the same, if the chain lifts a noticeable amount, say 2x-3x compared to the new/new test.
Time to go chainring hunting.
I have seen often where bikes lived in one chainring, either small or large. those are the bikes that need replacement of one faster.