Welcome to the forum Kendall.
For better visibility and replies, I have created a new thread for you.
Sorry to hear your tensioner failed.
How many miles were on the car when the tensioner packed it in?
I would normally recommend that you replace the tensioner any time they become noisy or present some bearing movement. (slight wobble may be seen) Movement may be felt when you try to pull up /down on pulley.
Mileage does play a role here as well. I normally change mine every 100,000 miles just to be on the safe side, and include a new belt at that time.
By your description of the sound being so faint, unless an auto stethoscope was used on the bearing, it may have been difficult to detect. However removing the belt and checking for play and spinning it, may have givin some hints, that it was due for a change.
1997 Buick Pk Ave (Soft Ride) Suspension!