... I never had a Selectric, but had I had one I'd probably still have it.
As noted earlier, I did and I do and I use it almost daily.
I used to love just watching the things work.
(I never understood how they didn't vibrate themselves to pieces.)
The weak spot was the dancing ball (the typing Element, as named by IBM).
• The lever on top of the Element was prone to snapping off if not handled properly or its retention spring could remain in closed position if part of the plastic broke off.
• The positioning teeth at the bottom of the ball could also break off (if one didn't handle the Element carefully). Fortunately, one could repair it neatly by pressing the bottom of the ball into a bar of soap, filling one of the depressions with Epoxy and then positioning the ball appropriately so that the created tooth would attach itself to the broken base.
I've still got a couple of the thusly-repaired Elements, and they still work just fine.
Slightly off the topic: IBM also had a variable spacing typewriter (where the width of the "m" was 5 times wider than the "i"). It made for a beautiful manuscript, but if you made a mistake you were SOL.