Probably the biggest factor for me when scheduling fall cleans is the direction and strength of the wind. Example-If it's windy and from the south, I look for an account with an area I can blow the the leaves to the north and into a clearing or woods. Sometimes its just not worth the hassle. It's hard explaining to the wife why I'm staying home that day since she doesn't have a clue how frustrating the wind can be.
Vacuum system on a mower helps a lot in windy situations.