You’re absolutely right, an investment in getting things done quicker, or getting other people to do these things for you, is a way of buying time. I never thought of it that way, GQ!
I can’t believe no one mentioned mortgages and loans yet. We can’t wait for everyone to save up till they’re 60 years old and are able to afford a house. We borrow money because we don’t have it yet, paying interest is a way of spending money to buy time. You could even say the US bought time when they invested 800 billion or so in the economy, last year.
Besides investing in your health, you might want to invest in technological advancements that helps you multi-task. Let’s use the example you gave in the question, the car. Wouldn’t you rather invest in a car that allows you to be a passenger rather than a driver. No longer would you have to spent your valuable time watching the road, you just freed up an x amount of time equal to your daily commute. Not to mention the 20 years of your life you waiste sleeping, those 7 years of your life you spend eating, those 92 days in your life you spent on the toilet, etcetera, etcetera. edit:: estimated on a regular lifespan of about 70 years.