A similar thread about a Ford Ka - same car, different dress - states the change interval is five years Yours is therefore due to be changed.

It can become very expensive if you don't have the job done - potentially a new engine.

Lots of discussion on the Fiat website about this old chestnut of a question. As usual, it boils down to how you feel about the wildly variable recommendations there are among different manufacturers about the length of time and distance a belt should remain in operation. Assuming nothing they drive seizes a belt should last the life of the engine if the basic design and material quality are good.

I would inspect it. A (presumed) mechanic has just posted on this very subject the observation that an 11yr old belt he has just changed looks as good as new - and it probably still is, having bedded in nicely. If it looks OK and sounds OK there is a good chance it will last ten more years.

The motor industry is duty bound to advise frequent change to minimise the tiny risk of future failure. Such failure is usually not the belt, but something it drives, usually a tension pulley or water pump. Some also fail after a recent belt change for such a reason, plus the additional risk of a poor quality replacement belt inexpertly fitted. I suspect there are thousands of cars on the road using more fuel than they should because the belt is a tooth or two out.

None of my old high mileage cambelts ever looked as though they needed changing but I once had to replace a stiff whining tension pulley before it seized and fried the belt.