John -  Basically Fraxel works best done in a series of 3-5 depending on your situation.  It's possible to do a more aggressive treatment but, if you can really only get one treatment, you may be better off considering a pixilated (fractionated) carbon dioxide laser.  It's possible to get more improvment with one  CO2 treatment especially with acne scarring or serious sun damage/wrinkles.

 If you are travelling, keep in mind that you will NOT want to get on a plane after a CO2 laser treatment for 3-7 days depending on the aggresiveness of the CO2 laser settings.  You will need some recovery time with this laser but one treatment will be more effective than one aggressive Fraxel treatment.  You CAN get on a plane a day after a Fraxel but you may be red and will need to apply the post-treatment cream  you are given  hourly on the plane.  Dr. I