Recently I went to get a Mobil 1 oil change for the Corvette. Although it had been only about 5,000 miles since the last one, and I've read that synthetic oils should be good for at least another 10,000, they also recommend it should be changed at least once a year. I also requested an alignment, since the right front tire was wearing more than the left one, although I hadn't noticed any steering problems.
I also mentioned that the right rear tire had a slow leak, losing about a pound a month. Since they'd previously given me a nitrogen fill to make up for an earlier service slip-up, I was expecting they'd just add another five psi and I'd be on my way. However, when they sought me out in the customer lounge, it wasn't to notify me that everything was ready, but to take me into the shop. The tire was off the wheel, and they showed me not only the small screw in the middle of the tread that was repairable, but also the really small nail that was angled too close to the sidewall to be repaired.
The new tire, including labor, balancing, and new tire pressure sensor, cost $516.40! Well, the rear tires are pretty huge – twenty-six inches tall with a tread width of nearly a foot – and specialized, capable of being driven flat for 50 miles at 50 mph, as well as, when inflated, at continuous speeds of "over 168 mph." Unfortunately, although they "had" one, it was in a warehouse that was two hours away. Fortunately, it was nearly lunchtime and the nearby restaurant they recommended was quite pleasant.
Also fortunately, the tire warranty I had purchased reimbursed me for the entire cost, although it required a half-hour telephone conversation between the shop person and the warranty people. It also required that I provide a date for when the damage had occurred! Since the air loss had been occurring for months, who knew? But I shouldn't have been concerned, it was just another box that needed an entry, so I chose a random date several months in the past.
In the end I was there for five hours for something I thought would take no more than an hour, since I had an appointment. And now the rear tires have 18,000 mile different diameters. It drives fine, but I have no idea if the difference might be enough to result in significant differential wear.
Update: In 2017 I traded in the car when I purchased a new one. The left rear tire, after 37,000 miles, was the original – my only tire-punishing driving has been at Ron Fellows' Performance Driving School, using their Corvettes. And there had been no differential problems in the meantime.