I'm 29 but I'm a mechanic by trade so I've scraped a few free of wax, you can never get it all off. Also had to add lead to that truck when we filled her up.There is no doubt synthetics offer more protection for a longer time. A lot of guys in here are to young to remember the old Quaker state oils. They added paraffin to the oil and man could you tell who used that junk when you cracked open an engine. Just a terrible blend. But the modern conventional
oils have come a long way over the last 30 years or so. All of mine that run conventional have looked like new the few times I've had valve covers or intakes off. In usually change them around 5500 miles or so.