The instruction manual with my smoke alarm specifies to replace only with an Ultralife lithium battery. Is the Rayovac 9V Lithium battery an acceptable replacement? If it is, how often should I replace it?

The RAYOVAC® 9V Lithium will work properly in any other smoke alarm requiring the Ultralife lithium battery. Under normal use conditions, the battery should power ionization smoke alarms for up to 10 years. Please note that smoke alarms should be replaced every 10 years, as they lose sensitivity over time due to age and dust.

Also note that many smoke alarms come with recommendations to replace the battery with a specific brand of 9V battery (oftentimes Alkaline or Zinc Carbon chemistries). The RAYOVAC® 9V Lithium is also an acceptable replacement battery in these devices and will power any ionization smoke alarm for up to 10 years.