Hard water stains... everywhere. There are tricks that maids use to clean water stains quickly and well. Will write about it later in a separate post.
Excessive dust (desert + winds + constant construction = all surfaces are dusty, all the time) Not hard for professional maid to clean. But can be annoying thing for a homeowner on daily basis.
Tile floors or natural stone floors. Our hot weather goes well with cool floors.
Long driving distances. Vegas is spread-out city. House cleaners spend a lot of time in their cars.
Animal hair. Vegas people love pets. Nearly every home has a furry friend or two, or five. Houses must be cleaned from all that fur!