When should I change the timing belt

Also, can it be examined visually for flaws or cracks?

The one thing I can tell you is that with this engine a timing belt failure will mean a new engine so the maintenance is rather important.

Here is the official recommendation of the manufacturer.

{34} On 2005 and prior years, under normal conditions, inspect water pump and replace timing belt at intervals of 105,000 miles or every 84 months. On 2006-10 models, under normal conditions, inspect water pump and replace timing belt at maintenance minder symbol 4. On all models, if vehicle is operated at ambient temperatures under -20 F or ambient temperatures above 110 F, inspect water pump and replace timing belt at intervals of 60,000 miles.