Customer comes with noise related to serpentine belt and I always explain why I want to do the tensioner also. Under warranty the manufacture never gave any trouble when a mechanic wanted to do the belt/tensioner at the same time. My Dealer wanted the customer to fill out that survey they get with 100% satisfaction marked and comming back for just about any reason was not a path towards 100% satisfaction. As a DIYer with an eye towards saving a few bucks I will give the tensioner a look over and if all seems OK I will use it again, but the squeak may not be fixed with just a belt change.