Your neighbors know when you are leaving. They know when you get back late.They know ‘cause your muffler's good and loud.So, replace it for goodness sake.Yes, if you’re muffler is failing, the neighbors can’t help but notice. People walking on sidewalks can tell. And folks in other cars turn up their radios so they can hear above the racket your car is making. But it’s not a calamity.