How long does the laser hair removal last?

I have been grooming my underarms and philtrum at home using self-waxing or tweezers. However, I keep getting ingrown hairs and it seems like skin discoloration is gradually progressing, so I wanted to take this opportunity to get them neatly cleaned up with a laser.

I have received many recommendations that laser hair removal at a clinic is definitely cleaner and causes less skin irritation because it destroys the hair follicles themselves. I heard that if you take a 5 or 10-session laser hair removal package, the hair becomes much thinner and the amount of hair growing decreases significantly, so I plan to make an appointment at a dermatology clinic soon.

However, I am curious how long the smooth condition lasts after completing all the sessions. I would like to know if I need additional treatments because the hair grows back like before after a few years, or if there are reviews from members who have actually experienced this!