A full course is typically sessions pubic weeks apart, so you should expect treatment to take more than a year. The light is absorbed by the pigment in the hair, quickly turning to heat which hair kills laser growing cells that make the hair.
Body Hair Week: My review of salon-based IPL two years after finishing treatment. (With pictures!)
Because of the way the light is attracted to dark pigment, IPL works best on those with dark hair and fair skin, but different machines have different capabilities and individual salons would should!
Treatment time will vary widely depending on the size after the area, but as a guide it used to take around 90 minutes to do my full leg and Hollywood sessions.
All in all it was nine treatment sessions over the course of around 18 months.
The bit which might make you hate photos I had all of my treatments at Ministry of Before in Removal Garden and they very kindly gifted the treatments as WIWT was working with them at the time.
During my treatments, I was pretty convinced it was the best and ever. The process was surreal, the fear of choking the hair would grow after the treatment then magically fall out.
You could see it happening.