It works, but it's not permanent. I had my thighs, chin and upper lip done over seven years ago - before I had kids. I don't like to shave my thighs, and because of the expense, I didn't have my lower legs done to keep the cost down. I'd really like to, but it's not in the cards for a while.
As I understood it, after several sessions, the laser kills the hair folicle (I don't think it has anything to do with the pigment of the hair as mentioned in a previous post.) What does matter is the pigment of your skin. They may have made advances since I had my treatments, but the fairer skinned you are the better, as darker skin has a tendency to be "burned" by the laser because it has more pigment in it. Anyway, your body can generate a new folicle wherever it wants, so over time, hair can develop again.
I continued some treatments after my first child was born, but I have not been back in years. I do have some hair on my thighs again, but it is mostly blonde and I am a brunette. It is also thinner so it doesn't concern me. I will probably go back for my chin and upper lip soon, as some darker hair is returning there.
You should also know that it can be painful, but all in all, I'd say it was bearable and worth it. You can ask them for a topical numbing creme to apply ~30 minutes before the procedure to help ease the pain. You may have to pay for it, and it wasn't cheap for me, but worth it. Basically, the closer the area is to the bone, the more it hurts. So the meaty part of my thighs weren't bad, but the area closer to my knees was worse. I have no idea how doing the area along your shin would feel.
Also, make sure the place you go is experienced. I started out with a dermatologist who as it turned out, rented the laser from another dermatologist's office one day a week. I only went to him once and that was a nightmare! For my next treatment, I went to the dermatologist who owned the laser. They did much more to prep the skin before and after. The difference was night and day. Even their fees were better, and the treatments got cheaper as I went along.
I wish I had had a forum back then to ask people about it. Good luck!