how often should the cerpentine belt be changed on a 2011 malibu

Ive always been inclined to think around 100k and have had several cars well over 100k miles with the original belt. It sounds like to me that a tensioner pulley or idler pulley is a little off or not doing its job.

i've had road debris cut into mine sometimes. inspect it often; especially rolling by accidents. some glass/metal debris can cut your belt.

it's usually good for 3-4 years