Just 4 planes. We have no dormers, and the house layout is a basic rectangle, with a garage on one side. So: 2 planes for the main roof, and 2 for the roof on the garage.
Mine has 9. And three of those are in the bay window I had added to the house, and another is from the when the prior owner expanded the attic to make it a bedroom.
The house across the street, still under construction, has at least 22, but I can’t see all of it, there may be more. I feel like the style has changed over the years. 
Three. Back, front, partial top floor.
8
2+1 for the main roof plus a dormer
2 for a separate roof over the back door
2+1 for a lower portion of a roof that wraps around to a different side.
My house was originally rectangular but was remodeled several times by an ape with a hammer. The original roof was a gable with 2 planes. Now it has 11 planes, most of which leak. If I ever complete my remodel, it will have 2 planes with a single gable covering a rather bizarre floor plan.
Frames done to plan in a factory. No more cost to frame than any other shape – more joins, but shorter beams.
By my count, 12 (including the garage) as shown in this picture:
4010903212_cd6aedbfe4_b.jpg (1024×637) (staticflickr.com)
… oops wrong house
Five on mine. Two in front - the roof on the left side of the house steps down about a foot from the center section. But only one plane across the back. And then a perpendicular “dormer” or whatever you call it over the garage on the right side.