When do you change a timing belt on 2007 Kia Optima?

According to the owner's manual for the 2007 Kia Optima, the timing belt should be replaced every 60,000 miles or every 6 years, whichever comes first. Some mechanics may recommend changing the timing belt sooner, such as every 45,000 miles or every 4 years. If the timing belt breaks, it can cause serious engine damage, so it is important to replace it according to the recommended schedule.