A complete reinstall of a modern Ubuntu on a spinning HDD takes less than 30 minutes in my experience (often less than 15).
Windows installs and reinstalls take hours more often than not -- just logging in for the first time on an up-to-date Win10 laptop recently took 10 minutes to "personalize" it for me ... and this was on an SSD. I used to have curiosity about how they made it so bad, but these days I've placed anything windows under a SEP field.
My last windows install was about 30 minutes from boot to actually on desktop (very frustratingly interactive though, blocking the last 10 minutes behind that personalizing dialog)
Some linux updates require a reboot for a kernel update to take effect; Many modern ones, if properly configured, can update the kernels without rebooting (e.g. Ubuntu, RedHat and Oracle all have that as a paid option for businesses, Ubuntu also free for personal or oss use).
But I've never had an issue where something wouldn't work between the end of an update and a reboot, where that does happen on Windows. Furthermore, it has happened to me that after a kernel upgrade (on a system that did require a reboot to make it take effect), I took a couple of weeks before reboot (running long simulations), in which case I was able to apply yet another kernel upgrade or two; but you only ever need one reboot to make the latest-and-greatest take effect.
On Windows, you accumulate reboots if you wait (which requires constantly rejecting the "shall I reboot now" prompts) so you may need many; and I've sometimes needed several reboots even though I didn't delay anything.
Live kernel patching is limited though: it can update most functions and some datastructures, but not all. This is great for bugfixes and security patches but can't deal with larger updates. If you're trying to keep on the latest version you need to reboot at some point.
Some distributions are switching to a more aggressive "reboot for any system update" model, with the system built on ostree or something of the sort. For instance, Ubuntu Core, Fedora Silverblue, or Endless OS. The update is downloaded and committed to disk (in a big, git-like repo for the latter two), but you need to boot into it. Your running system is untouched. This comes with the bonus that rollback is seamless: you choose an older commit from grub and it just works.
Of course, one key difference here is the system never tricks you into rebooting, and rebooting for an update takes just as long as rebooting any other time, so mostly (pending additional work, as usual :b) it's invisible.
I seem to recall Microsoft exploring similar to ostree with some Windows version somewhere, so I'd be curious to see how theirs behaves.
> Some Linux updates also require a reboot on some distributions.
AFAIK the only time this is the case is an update of something that can only be reloaded to get the updated version by rebooting--the most common case being the kernel.
Windows 10 Pro user at work, mixed MacOS / Windows / Lubuntu at home.
I've been on my work Windows 10 PC for 60+hrs this week, and about the same each of the past four weeks, and five to six days out of seven the past couple years.
And never had it force-update.
You can bet the moment I took this computer home (I won't, but humour me) and tried to watch a movie it would force-update, crash, refuse to boot, and need a full reinstall.
Actually domain joined Windows machines tend to keep their state when they can't see their domain controller. You would probably find, depending on config, that updates stop all together.