I have to say that I have used both Doing a Completely Clean Install of Windows 10 and Doing an In-place "Upgrade" to Reinstall Windows 10 Keeping Apps/Programs and User Files and have had excellent results with both.
If you really want to avoid having to reinstall a bunch of programs and restore data files it is my opinion that it is always worth trying the in-place "upgrade" first. I have yet to have it fail to clean things up, and quite thoroughly.
I just did one overnight on my partner's machine, and it's worked beautifully. One word of warning, though, is that you definitely need to revisit your Privacy Settings, your Power Options/"Choose what the power button does" in Control Panel to turn off Fast Startup, and check that System Protection is on if you want for it to be on. In the case of my partner's computer, Fast Startup was turned on again and I wanted it off, but the settings for System Protection (On) were carried over. We had also neutered Cortana way back in the day when you could do that using Windows settings and all of that carried over, too.
I used the "using the ISO" file method since I routinely download an ISO as each feature update version of Windows 10 comes along. I have also used the same method with a bootable thumb drive, which you don't have to boot from, just kicking off the setup.exe from it.
I figure since a non-thermonuclear option is available, and it makes life very easy when it works (and it always has in my experience), I try to avoid the thermonuclear option (completely clean install) when I can avoid it. It saves a lot of time (and, for clients, money).
jenae, if you read this, I want your opinion as to whether the step for the in-place upgrade reinstall that says you must turn secure boot OFF is actually necessary. I cannot see why it would be, since feature updates work just fine with it enabled and this is really the rough equivalent of a feature update by another means.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1809, Build 17763
Travel is fatal to prejudice, bigotry, and narrow-mindedness, and many of our people need it sorely on these accounts. Broad, wholesome, charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one's lifetime.
~ Mark Twain