how often should tires be replaced

Tires should generally be replaced when the tread depth falls below 1.6 mm, which is the legal minimum in many places. However, for safer driving, especially in wet or snowy conditions, replacing tires when the tread depth reaches 4/32nds of an inch (about 3.2 mm) is recommended. Tires also need replacing if they become damaged or after about 10 years, regardless of tread wear, due to rubber degradation. Additionally, most tires last about 40,000 to 50,000 km (~25,000 to 31,000 miles) or 4 to 5 years on average, but this varies depending on driving conditions, tire brand, and maintenance. Tire rotation should ideally be done annually or every 10,000 km to promote even wear. When replacing tires, it's best to replace all four at once for better vehicle handling, or if replacing two, place the new ones on the rear axle for stability.