Model S went into production in 2012[0] and has an infinite mile warranty for 8 years. These cars won't be out of warranty until 2020. It has no limit on owners and applies retroactively. Even tesla roadsters won't be out of warranty yet as they were produced in 08'. Given that there are about 2400 of them, most drivers won't pay out of pocket with a tesla for half a decade. The ones who bought roadsters are risk tolerant wealthy technophiles, who likely have repurchased Tesla cars. While I don't have data on that, if you pay over 100k for what was one of the first production electric vehicles from an unknown company and entrepreneur at the time, you have to be bullish on tech., the environment and have the funds to satiate your curiosity.

[0]https://en.wikipedia.org/wiki/Tesla_Model_S [1]http://www.teslamotors.com/blog/infinite-mile-warranty