4 or 5 slack outages in the last 12 months.
Happy to do the update at a quiet time (say 3pm on a wednesday before we go to the pub), but wouldn't do it during a major event (say the middle of the world cup final when we're monitoring things very closely)
If your service is off the public Internet, you now have a failure mode where the company VPN going down kills all productivity. And if you're going to have issues with a disk getting filled up, that's most likely going to happen with an on-premise solution than with a hosted solution where they have a team to take care that the disks don't "fill up". And not keeping your software updated because "an update would happen at an inappropriate time and we don't need it" sounds like a good vulnerability vector.