[unethical_ban]

For Ubuntu Desktop, it may make sense for the package manager to keep only the latest 2 or 3 kernels, and automatically purge the rest.

[pbhjpbhj]

I had the /boot filling up problem but had thought it was fixed, I'm on 16.04+. I'm pretty sure the last two kernel updates I did removed older kernels leaving me with the current one and previous one ... ?

[kobeya]

You can configure apt unattended upgrades to autoremove by default, perhaps you did that?

[cookiecaper]

Nope, still doesn't do it without manually invoking autoremove.