Too many Ubuntu reboot required updates lately

You can judge whether you need to reboot based on the CVEs being patched. Some things probably don't apply to your situation but the system tells you to reboot because it doesn't know. You can see them here: http://www.ubuntu.com/usn/

Hopefully rebooting for Kernel patches will go away by the next LTS, which should be well into the 4.x Kernel and therefore able to take advantage of the new rebootless shim updates.

Not only that, but in my case frequent kernel patches have been triggering this bug over and over for months:

https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-dr...

To the point that I hesitate to update the kernel promptly because I don't want to spend the additional 5 minutes to reinstall the nvidia driver and doublecheck that everything is working.

I've been happily installing them all (I've had at least 4 in under a month), because I have an extremely recent laptop, and every update fixes something else! (dell xps13 developer edition.)