According to the Home Safety Council, smoke alarms are an inexpensive, yet vital, way to alert you and your family in the event of a fire.
More Information:
The Home Safety Council offers these guidelines to help you install smoke alarms:

• Install a smoke alarm on every level of your home, even in the basement.
• Install a smoke alarm inside each bedroom, and outside sleeping areas.
• Affix smoke alarms in the middle of the ceiling or high up on the wall, a few inches away from the ceiling.
• Don’t install smoke alarms close to doors or windows, where drafts could hamper their performance. Also, avoid putting them in bathrooms, where steam could set them off, or in the kitchen, where cooking odors could set off “nuisance” alarms.
• Test smoke alarms frequently, and replace the batteries once a year.

But, as long as you’re going through the effort, I recommend that you purchase and install monitors that recognize smoke AND carbon monoxide. Both can be life saving for you and your family.