I had two of the original, early models with the single hole ATS-34 blade. Each evening, I would open and close the knife repeatedly (using my thumb to open the blade, and NOT fling the knife open). I also would often use the knives to do light household chores. (Used one more than the other.)
I ended up throwing away both knives, because on the one I used more, I had the lock fail on me during a very mundane task and the blade sunk into my fingers.
Prior to discarding the knives, I found that they both closed very easily with finger pressure. There was no lint or dirt in the lock, no discernable wear could be seen, and the knives were very clean. Nothing I could see would indicate why the locks would fail so easily on not just one, but both.
(The blades were marked "First Production Run", so perhaps there were early 'teething' problems.)
I guess I would recommend NOT getting one that's a First Production Run and be careful...
Regards,
Mike