Do ALL Jews have mezuzas?

[wehotex]

Or only the most observant ones?

[bobo1234]

My Dad's house has only one mezuzah and that's on the front door. He's Reform/Secular though.

[Tikva]

I have one on my front door and one on my bedroom door. It's not my house so I can't put them on every door in the house.

[usuario]

My fiancee babysits for a secular Jewish family. They do not have any mezuzahs.

We have mezuzahs at the entrance to every room except the bathroom.

[Pruzhany]

A kosher one at every doorway to a living area in the house and in the cars.

[JB from NC]

I have them.

[bobo1234]

Originally Posted by Pruzhany

A kosher one at every doorway in the house and in the cars.

Each car door?

[Pruzhany]

Originally Posted by bobo1234

Each car door?

Driver's door.

[HyperionGap]

Have one on the door to my apartment. That's all.

[wehotex]

Originally Posted by Pruzhany

A kosher one at every doorway to a living area in the house and in the cars.

How do you make it "kosher"? Is it blessed by a rabbi? Do you put it at the top of the doorway or the bottom? How does one determine how many doors of the home to place them? Is it a personal preference?
I'm sorry that I didn't spell the word correctly. I copied the spelling off of a retail store with a sign that said "We sell mezuzas".