I use capacitive styli a lot, so I’ve had and reviewed a lot of them over the years. I got the Wacom Bamboo shortly after it came out, and was more than a bit annoyed when the $30 stylus ended up with a ruptured nib. I actually ended up buying a whole new stylus, because I liked it a lot and there was no other option at the time.
Apparently I’m not the only one with that problem, and Wacom eventually came up with a replacement nib set. I mostly use my Maglus these days so I haven’t bothered too much with the Wacom, but I finally got around to picking up a set of replacement nibs. I still have the body for the stylus that ended up with a ruptured nib, so the replacement nibs actually both revitalized the somewhat worn nib of my working Wacom stylus and brought the old one back to life. Installing the new nib is easy: just unscrew the front piece, remove the existing nib from the metal piece it’s on, put on a new one, and screw the front piece back on.
Rubber stylus nibs are rather fragile, and they do wear out. More and more styli, like the Maglus and the Emote, now come with spare nibs as a result of that. Wacom is perhaps too large and greedy to bother with that level of service, but at the very least you can shell out for the replacement nibs now. They’re not easy to find in all parts of the world (I had to use eBay myself), but in the US you can pick up a three pack of replacement nibs for $8 on Amazon, which is a great price. If you have a Wacom stylus, it’s always nice to have a set of spare nibs lying around. Even if the nib isn’t outright broken, they do lose some sensitivity as they get worn out.