My daughter has a 2003 Grand Am. A few years ago the front OE tires needed replacing but she couldn't afford new ones. I found a nice set of Michelins with great tread on craigslist and they have performed well. But fast forward to today and she's running tires that are 7 years old even though they still have 6/32s. Replace because of age or ride them out since they are a name brand?