Well, you don't have to try to make your organisation safe from "every calamity", but it would be prudent to look at reasonable risks - like that your only deve

Well, you don't have to try to make your organisation safe from "every calamity", but it would be prudent to look at reasonable risks - like that your only developer becomes permanently ill, or wants to do something else at some point in his or her life. It is possible that in some business your competitiveness cannot cover the cost of mitigating this kind of risks, but then it's not a very good business.