[klausjensen]

The best lesson I learned from poker is the concept of "expected value". [1]

It takes some of the grief out of undesired outcomes - because you made the right decision based on the information you had, and chance just happened to not be in your favor in this case.

It affects how I make all kinds of business- and life-decisions. Chosing insurance-package on the rental car, investing in stock, trusting people etc.

[1] https://en.wikipedia.org/wiki/Expected_value

[fullshark]

> Chosing insurance-package on the rental car,

FWIW Insurance is a negative expected value "asset", but it makes sense to buy it (not in this case necessarily). A one time massive negative hit to your finances could be devastating compared to periodic insurance payments. Expected value is a simplified representation of the distribution of outcomes which is really what you should be thinking about regarding risk management.

[klausjensen]

As far as I know, it is not even possible for me to rent a car completely without insurance and thereby risk having to pay for the full value of the car. :)

So it is really about what kind of deductible you will have vs. what you pay for it.

If I save 100 EUR 10 times renting a car and I expect to have one damage costing me 1000 EUR every 10 times I rent a car - it is neutral EV.

If you can't afford the "hit" of a large deductible if an accident happes, then it would make sense to pay more here and now to reduce or eliminate that risk.

I have saved thousands of euros over the years by electing to go with the included insurance, which typically is around 1000-1500EUR deductible, if I remember correctly.

So if I crash my rental car the next three times I rent a car and have to pay 3x1000EUR deductible, I will still be in the green.

Last time I picked an upgraded insurace, it was because we were a group that rented together, and I didn't want to risk friendsships over who might have dented the car etc. :)

[fullshark]

I don't mean to defend this particular insurance, just point out that insurance is a negative expected value product (hence why insurance companies exist and are profitable) but it still makes sense to buy it a lot of the time.

[joelthelion]

You have that concept in poker too. It's called "bankroll management".