The lifespan is 10-15 years depending on the model. Most people were at moderate risk, unfit, drinking alcohol, poor exercise, high stress job ...etc. For moderate risk 10-15% is the stat over a 5 year period. Most where moderate a few, 2 I think, were low and we had a few high and one very high risk given he'd possibly already had a small heart attack.

Also note that you didn't take into consideration that the device is used for all in the office so over the 5 years it's cost must be divided by the number of employees it will cover which in this case was around 12.

Again your Meteor comparison was extremely poor. You are comparing something that is very common, a middle aged person having heart attack, to something extremely uncommon a similar demographic being hit by a meteor. Also to note that you can't say it it £250 to protect from a meteor strike it would likely be extremely expensive to protect an office from that versus the insanely cheap £1100 to almost guarantee that any of us survive a heart attack.

I've eddited to show the actual lifespan of the AED which is 10-15 year