A lesson for me, as others have mentioned, about updating plugins and how important it might be for some to KEEP older versions.
It is no big deal to open the newer version of a plugin, but not knowing what preset / patch / articulation, etc you used, and if the newer version even HAS the same setting available could be a mess.
The goal is often to get a sound back, and perhaps a lot of tweaking has been done both in the VST & the DAW, so being able to open it "as it was" could be important.
Of course how & where one saves presets is important. At one point I moved all preset folders to Non-OS drive and symlinked them, the aim being to retain all the extra presets I installed.
That way if a new OS install is needed all the presets are already there. Original locations may vary (for example, sometimes in User Documents folder), but that way all presets, including "user presets" are usually retained.
Another way, if you don't add lots of extra 3rd party presets is to have your own (non-OS disk) folder with "User presets" for all VSTs.
You can then create symlinks to those folders in the "User Presets" folder of the particular VSTs.
Of course backing up the whole system ensures that no matter what you can reload any setup even from years ago and have everything as it was (hardware changes being the only worry). With the cost of smaller SSDs these days, I have one reserved for a fast restore of backups, particularly useful when installing lots of new releases that may bomb, or finding after the fact that you did things in a disorganized way that will take more than an hour to properly fix, or there is uncertainty in fixing properly (due to ambiguous installers, registry concerns, etc). There are plenty of backup/restore options, but I got to using EaseUS Todo Backup some years ago. After getting back into the DAW scene in the past 3 years, I've quickly restored my OS dozens of times (often within 25 minutes, but at least within and hour total time, including reinstalling a few plugins or software I'd installed, reorganizing or settings changes,etc, since the restore time).
Instead of uninstalling a bunch of things I find I won't use, it gives me a better feeling (cleaner system) to restore from before they were installed and then reinstall those I want to keep that were added later. All my main stuff is installed early, so it's not that much to do regardless.
Wow...another long tangental post about backing up ... but if it saves one person a headache it's probably worthwhile.
I just need to make a sig with something about backing things up

 

And wanted to thank r4e again, since I was organizing my presets in Serum, which begins with installing the r4e 1.07b4 package
Anybody who has complaint about these forums or associated community, you just have to THINK a minute! Thanks @r4e

 

Last edited: May 5, 2019

Spot on. I always say my system backup (AOMEI backupperin my case) is one of my most important documents.
I restore from 2xHDD in RAID 0 to SSD so it flies.