According to the National Fire Protection Association (NFPA), aging smoke alarms don't operate as efficiently and often are the source for nuisance alarms.
Older smoke alarms are estimated to have a 30% probability of failure within the first 10 years. Newer smoke alarms do better, but should be replaced after 10 years. Unless you know that the smoke alarms are new, replacing them when moving into a new residence is also recommended by NFPA.