"In the long run, nothing beats great businesses, and nothing beats the satisfaction of ownership if those businesses are purchased sensibly" Frank K. Martin

Defensive Interval in days = ((Cash+Rec.) * 365) / (Total Op Ex - Depr. - Other Non-cash Charges) Taken from Graham & Dodd "Security Analysis" - measures expenses that could be paid with only currently available quick assets. Lots of companies now calculating for the first time.

Risks are those you cannot see. Public companies list ~8 pages of "Risks" in 10-k. Haven't seen one identifying pandemics as a risk to their business. You can never anticipate all the potential risks, that's why you need to build a margin of safety into your investments.