The belt on the 1.4L turbo does not have to be replaced until 10 years or 150K miles which ever comes first. Yes, some engines with timing belts require replacement before the 1.4L engine's time frame. Most engines made today also have chains as chains have proven to be much more durable and require much less maintenance. Belts were used alot in the 70's and 80's due to cost and weight measures. The times have changed however. Don't forget that the FIAT 1.4 litre FIRE engine is an extremely old design dating back to the early 70's. This fact is both good and bad. Obviously the engine has proven to be bullet proof and well made and designed. However, many small displacement engines have swapped to a chain due to the information above.
In theory, a chain should last the life of the engine and most do. Most new four cylinder engines are "interference" engines meaning that if a timing belt snaps, that extremely small period of time when the engine is turning w/o the benefit of the belt keeping everything in time can destroy the head of the engine or worse.
As far as the replacement of a belt being easier as compared to a chain, yes this is typically the case but I know in my Abarth, you literally had to remove the engine to replace the belt due to space restriction. I had no intention of keeping that car until a belt needed to be replaced. Not sure if this is true on a Renegade with the same 1.4 litre engine however.