[redshirtrob]

I've seen a couple mass layoffs. I survived one, but did not survive the next one a few years later.

This is very general advice and you need to correlate it with other events, but it's been a pretty strong indicator something was up: Keep an eye on your manager's priorities especially if they shift in a ways you can't explain.

One example from early in my career: Our manager abruptly became much less interested in product status and overall progress. To his credit he scheduled a call (we were a remote office) a couple weeks later in which he said the following: "Commit your code. Ignore all policies and procedures. Work at your own pace."

We suspected as much, but that call was the confirmation. Ironically, the organization was so large, and the layoffs so huge, they had to arrange financing just to complete the layoffs. This led to a one to two month period where we were employed, but had nothing to do. It was really weird. Generally we'd come to the office, play a bit of Half-Life, then adjourn to my friend's basement to work on the BattleBot we were building.