How many miles need to change the timing belt

Most vehicles should have the timing belt changed at about 60,000. What happens is the belt can stretch over time and break. When they break they could cause internal problem in the engine. If you do the timing belt it may not be a bad idea to change the water pump.

ASAP

2007 ION has a timing Chain and does not need to be changed normally.

Also, most timing belts today don't break in their own. More important are the pulleys that the belt rides on. They can wear and drag or even worse seize causing the belt to skip teeth or break. So when changing a timing belt you should change any pulleys and tensioners and usually come in a complete kit.