The only way to keep family recipes truly safe
What is an Air Gap? Air Gapping and Cybersecurity
The highest level of security for a computer is to have it air-gapped. It is the only way to make the chance of the computer being hacked as close to zero as possible. Anything less and a dedicated hacker will get in somehow.
The average person doesn’t need to have an air gap on a computer. This is primarily the domain of corporations and governments. For a government, it might be a sensitive database, project, or perhaps control of a weapons system. For a corporation, it might contain trade secrets, financial information, or an industrial process. Activist groups might also do this to prevent their work from being shut down.
You probably don't worry about these things if you only use a home computer. However, implementing just one or two of these measures will significantly increase your security.