Just installed 2020, and transferred over what I needed from 2019. Is there any reason to keep 2019 (2018…) on the computer?
They work side by side so there is no need to remove it and if for some reason 2020 doesn’t work for you then you can always go back to 2019.
It is generally recommended to keep both until such time as you find you really haven’t used the earlier version for a long time. Never remove it straight away.
Another reason for keeping older versions would only apply if you develop extensions, and want to keep them to test them to see whether they will work in older versions. People still use versions as far back as v8, though the number is dwindling.
I’ve developed a small number of extensions, and for that reason have kept both Mac and Windows versions running (though not all of them) and kept installers, back as far as v8 M2.
Eventually some will stop working or crash in later OSs for which they weren’t designed, and OS backwards compatibility isn’t perfect.
That makes sense, John.