Does the effectiveness of Botox vary significantly from person to person, even for the same area?

I am looking into Botox for the first time.
Looking at the reviews, the results varied quite a bit even for the same area.

Someone said it was resolved naturally.
I'm a little worried because someone said the change wasn't as big as expected.

What I want is rather than a noticeable change
It just makes the impression a little softer.

So I'm not really keen on getting a large amount right from the start.

Depending on muscle mass or usual facial expression habits
I am wondering if the effect could change.

When I get a consultation, do I just need to mention the effects I want?
Or I would like to know if it would be helpful to talk in detail about my usual facial expressions or daily habits.

How did you counsel those who received it for the first time?