Replacing drive belt

Just had the drive belt replaced as it was found to have lots of cracks... The mechanics suggested immediate replacement but as there wasn't any in stock within the vicinity I had to pick it up all the way from the Parts department at the Chevy showroom. The guy at Chevy recommended that the tensioner pulley be replaced as per standard procedure in a package. The supervisor of the auto shop where I get repairs and maintenance usually done messaged me that the drive belt was only required. As such, that was the only part bought and replaced. The question is: do you have to replace tensioner pulleys when replacing drive belt?

Peaceage

I replaced the pulley as well. I bought a kit which had all the parts and replaced them all. Others can confirm as the tension pulley has been known to fail.

belt failure due to the tensioner failure is just as likely as the belt actually failing.