If I need to receive treatment multiple times, would it be better to schedule appointments with a set interval from the beginning?

I'm thinking of trying Rejuran once, and if it's good, I'll continue getting it.
I am wondering how many sessions it is common to plan from the start.

After receiving it once and checking the skin condition
I would also like to know if it is okay to add it when needed.

For those who have received it multiple times, I am curious to know from which session your satisfaction level changed.