It's definitely a case of YMMV. I have had really good results after just four sessions, each four weeks apart. Some areas have not had any regrowth since the first session. The more stubborn areas (lip and chin) have very reduced growth and the only grey coloured skin is on the top lip (but this has really faded and is barely noticeable now). I barely get any regrowth of dark hairs between laser sessions so I expect by the sixth or seventh session I'll be pretty much done on the dark hairs
Unfortunately I'm still left with a few white hairs on my chin so once the laser is through, a small amount of electrolysis will follow
Overall I am so pleased with my choice to do laser first. Hopefully you'll get similar results and as you look younger than me, you might not have the problems with white hairs