Perhaps I should have said a fresh start every 3 or 4 macOS versions is better…a lot of cruft from no longer used or maintained applications and the like gets carried along…so every few years perhaps a fresh start is worth it. The problem is that it’s such a pain in the rear that few of us do it unless forced into it…it takes so long to get everything reinstalled, serial numbered, configured, and setup with preferences and toolbars and whatnot that we just don’t do it.
Hence my thought about using MA from a clone that I spent an hour or so cleaning up before doing the MA thing…in particular I always look in startup items and places like that for things that I clearly don’t need any more. OTOH, I can’t really tell you how much assorted Adobe crap is in my library folders that I have no idea which pieces are needed and which are cruft. The only way to fix that would be to nuke it all and reinstall Lightroom, Bridge and Photoshop with my Photographer’s Bundle info…and I would hate to muck up a decently running machine.
Just for instance…in my ~/Library folder I’ve got 16 folders with 2012 dates on them…11 are completely empty and there’s one for an old version of GraphicConverter, one with some Automator actions in it all dated 2012, one labeled PubSub with a sqlite database in it that I have no idea what it is for, and so on. Similar folders exist for every year since then and I know a lot of that is worthless. Since the startup and login processes look for things like startup items, launchd, or similar auto launched stuff…clearing out a lot of old stuff makes some sense.
My current 2015 rMBP has been upgraded every year since it was new via the install over the old OS method…and there have always been the odd strange beachball occurrences and mysterious pauses like it’s looking for something and not finding it. Makes me think that maybe when I upgrade to an apple silicon laptop it might be worth doing a more thorough scrub or perhaps reinstall apps and such and just accept the hours/days/weeks it will take to get things ‘right’ again.
To a large extent…the fresh/migrate is just like better being the enemy of good enough…there’s a point when it’s not but redoing everything once a year when we get a new macOS is just too hard for most of us.