Know who would pick up if you called with bad news and no explanation. That list is short. Protect it.

Most of the people you talk to regularly are not on this list, and that is normal. The list is made of people who would answer at an inconvenient time without needing to know what it was about first. It is short for everybody, usually two or three names, and it is not the same as your most frequent contacts. Knowing who is actually on it is worth doing before you need it.

Write the names down for yourself. Then do the small maintenance those relationships need, which is mostly replying and turning up. And make sure you are answering when somebody is calling you at a strange hour.