Ok, in worst case, one needs to work a bit longer. If you’re scared of that possibility, then you should lower your market exposure - but in that case, surprise, surprise, you will also have to work longer due to lower expected returns in case there’s no crisis in the near future. I don’t think there’s a sure way around this - most likely you just need to be flexible and stay invested.
Big ERN has an awesome blog, but as a former FED analyst he’s too focused on economy fundamentals - for example, in 2008 all major economic indicators were positive and most economists, including FED economists, were positive about the state of economy. Crash was unexpected. It usually is unexpected.