The idea that timing belts must be changed at 60K seems a little suspect to me given the improvements in manufacturing over the past 20 years. Yeah, I know you can't tell if it's about to break beforehand, rubber deteriorates, the expense of repairing bent valves etc. is many multiples the expense of proper preventive maintenance, etc. But, the cost of a timing belt change is often about $500 these days, and worst cast expense of fixing a typical engine with catastrophic belt damage is normally less than $5,000. So, when you you suppose the odds of timing belt breakage approach 10% for the typical engine?