[riolu]

> 1) app is buggy and I'm trying to fix it by reinstalling from scratch

You don't specify and it's highly dependent but in most cases when an app is misbehaving it's an issue with preferences. You can reset most apps with `defaults` without blowing away all its data. There are some intricacies with how macOS handles preferences, so you should avoid manually editing related .plist.

[throwaway290]

Note that if I am trying to fix an app that I want to keep using I sure as hell may want to keep the preferences.

The case where I want it to auto clean up is where it is repeatedly broken and I never really got to using and configuring it yet. It's pretty rare.

[riolu]

> Note that if I am trying to fix an app that I want to keep using I sure as hell may want to keep the preferences.

Of course, `man defaults`. You can modify the preferences and potentially fix it, backup preferences, etc. Again I must stress that you use `defaults`, the .plist on disk isn't always accurate even if you terminate the app and reboot the machine.

> The case where I want it to auto clean up is where it is repeatedly broken and I never really got to using and configuring it yet. It's pretty rare.

There isn't really a one size fits all perfect automatic solution. Not all apps are good macOS citizens.