Why Differences in Timing?

And I’m confused about the different opinions on when treatments should be done.

I’m getting underarms, bikini/brazilian, and upper/lower legs done with a Lightsheer Diode Laser. They tell me my optimal treatment timing is about every 11-12 weeks.

My friend, who will be using the Aurora IPL, is having the same areas done and they have told her that the ideal treatment timing is every 6-8 weeks.

And in searching this website I have found varying timing recomendations - anywhere from about five weeks to the 11-12 that my people have recommended.

Why are there so many different opinions as to timing? What seems to be the “norm” for timing? And what would most people consider ideal timing?