I asked on of the Avon guys at the boat show">London Boat show, and he said 20-25 years, but a lot depends on whether it has been sitting around under the tropical sun.
Boat: Morgan 33 OutIsland, Magic and 33' offshore scott design "Cutting Edge"
Posts: 1,594
Heard same thing from viking who told me navy has plenty still in service after 20 yrs. When its repacked it its gone over thoroughly, they'll let you know if its expired.
I don't have hard data, but where I live (Hong Kong) High humidity, high temperatures the lifespan is considerably less than 20 - 25 years. I have had experience of having to replace a 8 year old raft - regularly serviced, reputable brand.