Mar 10, 2010

Should you live like you're about to die? (a suffocatingly rational analysis)

This is a question I have been thinking about a lot lately. At first the answer might seem obvious. Here's Steve Jobs:

Remembering that I'll be dead soon is the most important tool I've ever encountered to help me make the big choices in life. Because almost everything — all external expectations, all pride, all fear of embarrassment or failure — these things just fall away in the face of death, leaving only what is truly important. Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart.

But choosing to live this way has serious consequences. Consider:

If you expected to die soon, would you...

Work the same job?
Read the same books?
Save/spend as much money?
Spend your money on the same things?
Spend the same amount of time with friends and family?
Talk about the same things?
Think about the same things?

The bottom line is that people live radically different lives depending on how soon they expect to die, and rightfully so.

The crux is this: For certain things like saving for retirement we can make decisions based on life expectancy, but for most things it's not so straightforward. Say you have a 0.5% chance of dying this year -- it does not make a lot of sense to spend 0.5% of your time living as if you are about to die; you must choose between living as if you (a) will die this year, or (b) will not die this year. There is no in-between. But how to decide?

Here is where the suffocatingly rational analysis come in. It is almost painfully rational, but if you stick with me I think you will find it somewhat revealing. Or chicken out and go straight for the results, if you must.

To wait until the year you have a 50% chance of dying to start living like you are about to die would mean waiting until the ripe old age of 107. (Sorry, but you probably won't make it that long.) A rational approach has to take into account more than just the probability of dying -- it needs to consider the expected value of dying.

Expected-Value(Living like you're about to die at a given age) = Probability(Dying at that age) x Magnitude(How much you'd like to avoid dying at that age)
EV(Living like you're not about to die at a given age) = P(Not dying at that age)

To cut down on the wordage:
EV(Death) = P(Die) x M(Death)
EV(Life) = P(Live)

So if EV(Death) > P(Live) for a given year then better to live like you're about to die.

The probability of living and dying is easy to come by (see this actuarial table, for example), but to determine how much it would suck to die (as compared to how pleasant it would be to live) is internal and subjective.

I should probably take a moment to clarify this "how much it would suck to die" business. Of course after you're dead the suckage is over. I got that. This is getting more at how strongly you want to avoid dying. You can imagine how this changes with age and life events -- newlyweds and expecting parents typically want to avoid death more than disgruntled teens or elderly people with chronic health problems. To give this concept a numerical value, we must compare it to the baseline of how pleasant it would be to live.

Look at it this way: Let's say you know for certain that you are going to survive this year. That gives you a certain pleasant feeling that we will assign the quantity of 1. Now, let's say you know for certain you are going to die this year -- compare the magnitude of this feeling to the one we just assigned a quantity of 1. Is it 10x stronger? 100x? 1,000x? If so, the value you would input for how much it would suck to die is 1,000.

Using the method above, you can input your estimates and solve for whether it's better to live like you're about to die. Another exercise we can do is set EV(Death) = P(Live) and solve for the break-even point. I have done both in this spreadsheet.

The probability of dying in a given year (taken from actuarial tables):



The break-even points = P(Live) / P(Die):



This shows that at age 10 the suckiness of death must be nearly 10,000x stronger than the pleasantness of living for it to be worth living like you are about to die, while at age 60 it need only be 100x stronger.

The chart below shows the later ages better:



Finally, I inputted some of my own estimates to come to a conclusion. I assumed the suckiness of dying peaks between the ages of 29 and 36 at around 160x (totally arbitrary) and stays strong through the 50s before steadily declining to 20x at age 90. (Nerd note: I also subtracted a constant of 20 to represent the suckiness of thinking about your impending death.) Below is the resulting chart, which I find thoroughly fascinating.



My estimates suggest that it is best to live like you are going to survive until about age 70, after which the clear choice is to live like you are going to die. That is until (and unless) you make it to age 90, after which it's best to go back to living like you are going to survive.

I find this all weird, fascinating, and a little confusing. Would love to hear your thoughts.

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Now, to take a slightly more nuanced and less suffocatingly-rational approach:

I think the choice for whether to live like you're about to die should come down to certain domains.

When it's best to go strictly rational with life expectancy estimates (like above)...
  • Saving and Spending.
  • Level of investment in your own learning, skills, or education.
  • Certain aspects of the type of job you choose and how long you do it for.
  • Diet, exercise, and lifestyle.
  • Time allocation in general.

When it's best to assume you are about to die...
  • Level of interest, curiosity, and passion for the things you do and for the world around you.
  • Appreciation/gratitude.
  • Attitude towards and affection for others.
  • All those other words that do not convey well-enough the feelings I wish to express.