I'm curious about the duration of laser hair removal.

I know that laser hair removal has become very popular these days and is being received by people of all ages and genders, but I am curious about how long the effects last, how to care for the skin afterward, and the recommended number of sessions. Of course, for people with "steel hair" like Jeon Hyun-moo's that is incredibly thick and doesn't thin out no matter how many times it is done, the recommended number of sessions would be higher. However, how many sessions are recommended for the average woman's typical arm and leg hair? I am also curious about the interval between treatments and how long the smooth results on the arms and legs last once the recommended sessions are completed.

Also, I'm wondering if I absolutely shouldn't go into the sea after laser hair removal, right? If I do end up going to the ocean, would it be best to stick to the schedule and complete all the recommended sessions before heading to the beach or a swimming pool? Please also let me know if I have to give up on my summer vacation this year. I guess I should have gotten the laser hair removal done before summer arrived. Now that I'm trying to do it right at the last minute, there are so many things holding me back. ㅠㅠ