Does being mentioned by AI actually mean your AEO is working?

I have been testing how different products show up in AI answers and noticed that getting mentioned doesn't always mean much.

A product might be listed alongside several competitors, get recommended without its own website being cited, or disappear entirely when the prompt is worded differently.

So I am curious how people actually measure AEO success.

Do you look at mentions, recommendations, citations, position against competitors, referral traffic, or something else?