Mine has worn in enough to start jamming up, but I've mitigated that by pressure washing it at our water park almost every day. That helps a lot, but I've been reluctant to actually lubricate it, not like I want oil on my hands every time I tinker with it..
Advice very welcome, as the puzzle you see above, I can solve it blind and single handed, but the thing keeps jamming up..
Update: I figured out where the main wear and tear is coming from. I used a cloth wipe to clean all the crevices of plastic dust. Then I noticed circular grooves worn into pretty much every piece internally.
Turns out, it was caused by plastic burrs from the clips on the covers of the center pieces. If I had realized that to begin with, I would have flattened those out and cleaned them up when I first had it disassembled.
Anyways, now it's already pretty well worn in, no reason to bother now. Still, if I knew in advance, I would have trimmed, smoothed out, and lubricated those manufactured plastic burrs before even using it much.
That's right, it goes in the square hole..