Interesting replies, thanks!
I have spent a lot of time researching the issue of belts breaking, and nearly always it seems to be on older, or more accurately, older day, vehicles. The exception is where the belt has been replaced and usually it is then quite soon after the job.
However, the motor trade has capitalised on the fear factor and created a huge aftermarket income source.
In my case, my wife’s Renault Mégane, cambelt broke within a day of the service, that was in 2002.
However, with my Fiat based motorhomes, and my 5 Ducati motorcycles, I have monitored rather than changed the belts over the last 15 years. The bikes do small mileages, therefore changing a belt every two years, as recommended, seems wasteful. It is quick to take the plastic cover off and examine the entire belt. So far they seem as good as the spare I have had in stock for some years.
For motorhomes, the distance is also very small, compared to the expected use of the base commercial vehicle, so also seems a wasteful exercise.
Finally, if age is the problem, why is that belts do not have a manufacture or use by date on them?
I bought one to convert, an 03 model, I needed advice from Renault, it was so confusing I sold the van and bought the Relay.