I am wondering how long the effects of Botox last.

I am considering Botox because of my forehead wrinkles.
I am most curious about how long the effect lasts.
I heard it usually takes 3 to 6 months, but it seems like there is a big difference.
I am also curious why the duration of maintenance varies from person to person.
I am also confused about whether lifestyle habits have an influence.
I am also worried about whether I should keep getting hit once I get hit once.
I am curious what the most important point is when getting hit for the first time.
I am also worried about whether it will stay naturally.
I would like to know the criteria for the duration.