pt limited 03 78000 miles..change timing belt?

Age in this case is irrelevant, it's running fine and well under the recommended mileage for replacement, so I'd leave it alone.

My mechanic told me change it at 100,000. If it breaks the engine can seize up.

I just had mine changed at 80,000 + the serpentine belts anf the motor mounts.....little over $1,000.00