Many laws require that you install at least one smoke alarm on every level of your home. It is also important to install at least one fire extinguisher in a convenient location on each level. The most basic protection for any home would be to install one smoke alarm and one fire extinguisher on each level. However, check your local building code since many require alarms also in each bedroom. 

Other important considerations include:

1. Mount smoke alarms in the middle of the ceiling when ceiling mounted. If that is not possible mount detectors on the wall at least three feet away from a corner and 4 - 6 inches away from the ceiling.

2. Keep smoke alarms away from drafts created by fans or air ducts. The moving air can blow smoke away from the sensor.

3. Avoid placing smoke alarms too near the kitchen stove and bathroom shower, as cooking smoke and shower steam can cause nuisance alarms.

4. Mount basement alarms at the bottom of the basement stairwell.

5. Mount fire extinguishers on a wall 3 1/2 to 5 feet above the floor. The location should be near an exit or an escape route from the room.