I would send an apology and then rebuild my workflow so I'm not asking them to shut down their systems at night. Why would you need them to do that? Saving electricity?

I have a daily nag that pops up after 14 days of uptime, reminding them of the importance of regular shutdowns/restarts. I annoy them into compliance.

Beyond that I force restarts as part of my monthly patches so I'm getting at least 1 restart a month.

Honestly, any reason you come up with to convince users will be ignored. They will only reboot if they experience an issue, and you have entirely different motivations that they don't care about. Users are not known for following "best practices" and properly maintaining their devices.

I am on board with nagging or having a monthly "patching" reboot (if a patch requires it or not) with some sort of deferment option over a week so they have every opportunity to do it themselves.

I have a jamfHelper that pops up at 4 days since last boot. It gives them the option of a 2 minute, 5 minute, or 1 Hour delay. Is seems to be working pretty well.

Interesting discussion!

My personal take is: Why make users shut down? If this is an energy saving measure... gotcha!

If you're doing it for preventative maintenance then you're in gray territory. While rebooting a Mac can fix issues, I'm hard-pressed to say there's evidence of it preventing issues.

I like @hkabik's method of restarting as part of patching. To me, that's routine enough.

I'm going to have to agree with the general crowd here. While there is certainly cruft that crops up after many months of continual sleep cycles, it's not horrible. You'll have security patches that will require a reboot from time to time and those can and should be enforced. That should give your users a reason to reboot every couple of months.