Make sure the weather-seals on and around your sliding patio door are NOT painted. If the weather-seal is painted it will affect the integrity of the seal and the dried paint can be heard scraping each time the door is moved.  According to Industrial Spray Painting Experts weather-seals encrusted with dried paint can be easily replaced.  Also, you will notice that the painter cannot reach the vertical parts between the frames where the panels interlock, .  these areas can only be painted when the door is removed.  You may become accustomed to the fact that these areas are not painted, but your guests will notice, check out some ideas for your garden.