Never had any problems with mine, except for one time I misplaced my insert for some GT Trades I had laying around for about 6 months or so. I decided to put them together, and couldn’t find the insert. So I bought some off of e b a y, and they were real loose. Of course I never glued them in.
When you are installing the inserts do they slide in fairly easy, or do you have to slightly force them in?
They make a round wire brush for roughing up the inside of the shaft. The only other thing I could recommend is, stop hitting things that are hard.
Good luck.