So when Mojave gets released, I have to upgrade no less than three computers (work laptop, home laptop and gaming hackintosh). Previously I’ve always just formatted the disk, then installed and finally imported my User from the backup drive using the migration assistant. I’ve tried just upgrading without formatting in the past, but something always went sideways for some app, so I decided many years ago just to do it this way.
Of course, the Hackintosh is a separate story, usually I wait months to upgrade it, and even then it takes me days to get it working right. Honestly, it’s not really worth keeping macOS on it now that I could just get an external GPU for the home laptop, but it’s less than two years old, so I’ll keep it for a while yet, I expect…
However, this year I’ve started keeping a dotfiles git repo (private, with certificates, keys and everything) with a Homebrew Bundle file (https://github.com/Homebrew/homebrew-bundle), which I not only use to keep settings, apps and some files on the three computers in sync, but which now seems like a cleaner way of upgrading - I could now wipe my computer and reinstall in like half an hour (not including wait times) whenever something weird happens.
Of course, I expect I have to go back to the backup several times to get files I don’t have in the dotfiles repo right now, but going forward I could just add them, so this is sort of a first iteration solution.
So how do you guys upgrade?
Edit: I feel I have to clarify. I am in no way forced into this. If I wanted to, I could just upgrade and deal with any issues. It becomes a bit of a “how clean can I get the computer and yet be up and running again in the shortest possible time if the lightning strikes” challenge after you’ve been doing this for a while