2000 RX300 purchased new, always serviced by dealer, now over 8 years old, with only 40,000 miles. Should timing belt and hoses be changed on basis of age rather than milage ?
I wouldn't. The quality of the hoses and belts on those cars is tip-top. I'd wait until the recommended service interval for the timing belt and only replace the hoses as needed. The new rubber compounds are capable of lasting for a very long time.