I have never seen a handover being very useful. Nobody has time to receive the handover and if the system is not a total mess, other people will get up to speed quickly as needed. Every time I have seen somebody leave or being laid off, things just moved on without much problem.

I've had the exact opposite experience. Referring to hand over notes that I'd taken years earlier when something unexpected came up to a system that still ran but no one actively was working on.

Here's the thing I've learned lately from friends who have survived layoffs: handover often doesn't happen.

The company terminates access effective immediately (maybe with gardening leave) for security reasons.

The immediate loss of institutional knowledge causes fucking havoc across the board.

So some people will be taken back on as contractors for a while at extremely expensive rates.

This also means there's a weird incentive to start hoarding knowledge if you suspect layoffs are coming down the pipe...

This happened to me. Was the sole developer on a certain service. Other engineers would use the service at the company, but no one else really wanted to get into it and work on it.

Was working on fixing an issue one morning, got roped into a meeting, and escorted from the building. Next week, saw an email from a coworker asking how to do something with the service. Told him, politely (don't burn bridges) that I didn't work there anymore and wasn't interested in helping that company without payment. Yeah, it might be thought of that I hung him out to dry, but that wasn't my intent. I just won't work for free, particularly when I was booted without much chance to get my affairs sorted

This happens all the time and the downstream effects of hazardous layoffs are often not seen or felt until Jim the resident container expert isn't around to restart the critical containers that all of your other services need, so you start losing a lot of money and time as John the replacement scrambles to figure out how the system works and what to do.

Or they get hired back as a contractor for 3x-4x the hourly wage as you mentioned.

And then more good people leave too, as they're more willing to accept other offers.

I got 0 hours notice -that's fairly common, in the US. Usually, you aren't even allowed to go to your desk, and collect your stuff. You have to schedule an appointment to come back, after work hours, and be escorted there by a security guard.

I (and my team) already knew it was coming. The writing was on the wall, and we had our affairs in order. My Japanese manager appreciated it. I think the American HR manager was a bit disappointed that there wasn't much of an opportunity for the casual bullying and shaming that they do, in these circumstances. The last HR manager was OK. I had zero respect for his predecessor.

HR had the highest turnover of any department in the company. I tended to have a somewhat adversarial relationship with most of the HR managers, but the one that I respected most was fired in an explosion, more than twenty years ago, and now manages a much more prestigious organization. I sincerely wish her well, and she has my respect; little as I'm sure that means to her.

In Marketing and Sales organizations, it's common for people to be walked out the door, immediately after handing in their resignation.

Who cares? You don't work there anymore. Not your problem.

Twilio fired 17% of its staff. There was no handover.