You cannot. iOS is one problem, but it goes for every other device/server/desktop/appliance that you use. You can take a lot of precautions, and mitigate so

You cannot. iOS is one problem, but it goes for every other device/server/desktop/appliance that you use. You can take a lot of precautions, and mitigate some risk, and ensure that operations can continue even if something bad happens¹, but you cant ever "be safe". ¹ "" There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know "" (Often attributed to Donald Rumsfeld, though he did not originate the concept.) Know what bad can happen is difficult.