Originally Posted by
randya
only a novice takes the pin entirely out of the link; and if you don't take the pin entirely out of the link, you are, by definition, reusing it.
You have to push the entire pin out on most chains made for 7-speed and narrower and replace it with a special pin that guides itself into place (and isn't reusable either). The guide is snapped off the end of the pin once you've inserted it. Shimano pioneered this little system; SRAM uses the much more intelligent master link.
If you don't use the replacement pin, the original won't fit parallel with the outer plate, cracking it.
-Kurt