While time passes, workers /boot partition can become full (right now there were 3 of them > 90%).
It seems that continuous updates keep all old kernel versions around, unless we remove them...
Right now I've just executed a quick sudo apt-get autoremove to achieve that manually.
This is about to add the execution of that command (and maybe others if needed) after every upgrade is performed. This is what I execute in general for debian/ubuntu boxes, for reference as possible thing to automate alltogether: