I got rid of 8.5.3 some time ago, and X1 about 6 months ago or so.
I have retained X2, and of course X3e.
I tend to keep releases of Sonar for 2 reasons: first, so I can finish projects started in a given release, and second, to preserve components that were dropped - such as V-Vocal and BeatScape, etc....
As time passes, I lose reliance on needing the old versions, and then I end up removing them.
They are not particularly big, the above is just my take on them, and it works for me.
Bob Bone