Is the number of shrink shots very important?

I looked into consultations, and it's even more confusing because the number of shots recommended varies from hospital to hospital, even though it's the same Shurink treatment.
I don't think getting a lot is necessarily good, and I wonder if it depends on face size or problem areas.

I am more concerned about my chin and lower face area than my entire face. Do I still need a lot of shots in this case?
For those who have received it, how did you decide during the consultation?