How are the diagnosis and treatment intervals determined before starting melasma treatment?

Hello. My melasma seems to have darkened a bit recently, so I am planning to consult with a clinic about a treatment. I have found that there are various types of melasma treatments available, so I would like to consult first to determine which method is suitable for my skin. Before starting treatment, does the clinic establish a treatment plan after assessing the depth and extent of the pigmentation and skin sensitivity? I am also curious if I can be informed of the estimated number of sessions and the overall treatment duration during the initial consultation. I would like to know if the existing plan is adjusted if my skin condition changes during treatment, and how long the intervals between sessions are typically set. Additionally, I would appreciate it if you could let me know if there is any skin-related information I should provide in advance when scheduling a consultation.