When you'll brake a belt many miles away from home, You'll learn to love chain.

Chain advise you before brake.
Chain starts to become weak and noisy when used.

You can also see sprocket teeths lightly bended when it's time to change them.

Modern chains don't brake easly like before.

A belt can brake without simpthoms. Sometimes is sufficient to run with front and rear sprockets not perfectly aligned to damage internally the belt that will brake without advise.