I found 4 life jackets dated 1980 from the previous owner. They inflated just fine :)

The yachty forumsare full of these sort of horry stories bout this time every year - if nothing else it drums up a bit of business.

I would suggest that if you own a life jacket you simply open it up and check whether 'all the bits' are still attached. The most common failure is similar to that noted earlier - the cylinder or release mechanism comes loose - and naturally the jacket does not inflate.

For boating I have some autoinflation jackets - and they have a real tendency to self actuate when damp or heavily used. The manual ones I use in the aircraft are much more reliable. All of them use the same clyinders and other bits which are readily available from yacht chandlers. In my opinion it is far better you know what is in the wrapper than simply sending it away.

And FWIW when I bought my old Terrier it came with an ex-British Airways passenger jacket - at least 20 years old. Out of curiousity we pulled the string and yes it inflated.... Our liferaft is now aroubnd 18 years old and has racked up three service visits - it will be interesting to see how long it is judged to be fit.