If NFPA takes replacement figures from companies like Honywell, ADT etc, and im sure they do, then the figures are BS considering what has happened to me at several buildings. I get a false alarm, I would call my alarm co. They would send out a tech who would immediatly keep the complete conversation on how its best to replace all sensors because of age. This started about 15 years ago. After a few false alarms I started cleaning the detectors myselfe but realised my failures were bugs or dust, In about 25 years with the same sensors, all false alarms were bugs or dust.
Understand the motive the tech has, he can likely make 5x more every day, in kickback, if he can sucker you into replacment of a part ranther than charge for just time. At the 150$ I was quoted per sensor there is enough padded in that price, [ probably 7-9x markup] to give the tech a nice incentive bonus to sucker you on a new unit.
My opinion is those figures, and the fear of replacement are pure BullShit. I look at it like a new car dealer, take any new car in after 15-20000 miles driving and if you tell them just fix everything, you will always walk out $500-2000 poorer.
I say test your detector and blow them out every 6 months, save your money, its possible to get defective chinese crap anyway.