You retire when you are sick and when you can't do it any more or when the public retires you. That's the most painful, because that's the one that leaves you wanting to accomplish more. ↗
Firstly the cars aren't too complicated. They have no traction control, for example, which means you can spin if you try too hard and damage your tires if you're not careful with your driving style. ↗
Having once decided to achieve a certain task, achieve it at all costs of tedium and distaste. The gain in self confidence of having accomplished a tiresome labor is immense. ↗