Originally Posted by TheOtherDave™

90K miles is the typical replacement interval, but since it degrades with heat, there's a time component as well.

Obviously, replacing the belt is much cheaper than repairing the top end after it snaps. I would replace the belt now unless you have proof it was done in the last five years.

It's the noises you describe that makes me think your timing belt tensioner is on its last legs. You might get luck and only jump a tooth or two when it fails, but I would not take that risk.