Most people have heard that you should change your smoke detector batteries every 6 months as you change your clocks for daylight savings time. This is a safe and necessary habit. Something that is not as well known is that you should change your entire smoke detector every 10 years. The National Fire Protection Association (NFPA) , the National Association of State Fire Marshals (NASFM) and FEMA recommend this timeline. They also recommend that the old style battery operated detector be replaced with a 10 year sealed lithium battery model. Since the battery cannot be removed there is no danger of the battery being removed for false alarms (cooking, etc), borrowing the battery for a toy or other device, or just plain forgetting to replace it. For the whipped cream on top, this turns out to be a good investment. If you use a decent alkaline 9V battery for your smoke alarm (safety is not where I skimp) it will cost you $35.20 in batteries (2 times x 10 years x $1.76 per battery). In the Dale Electric Catalog we carry i9010 basic model which sells for $22.79 or the P3010K-CO which is also a CO Detector and only cost $54.07. For me this is a no brainer, the only decision that I need make is whether I need to have a CO detector. Less money spent, less labor and a safer existence.