I've had my one and only GGTS going on 5 month. I picked it up in the classifieds and finally decided to check and change the button spring on my #652. Made a huge difference.....lesson for me: Keep the GG "fresh" to maintain your top notch performance....from the looks of the old(left) I wouldn't be surprised if it had never been swapped out though performance loss seemed very gradual thus my delay in replacing.