Don't throw away your nib-eating Wacom! Feed it. Make your own nibs with .065" trimmer wire/string (the type you use for lawncare). fits perfectly, works perfectly, its only plastic. They're even more durable than the standard nibs. I've been on the same one for weeks - and I have 3299 left. (I bought a 250 ft. spool for 8$). The process is on youtube "Wacom Nib Wear Solved - Low Price Nibs". It's simple, just cut a 1 inch piece, stick it in your pen and laugh at the people paying $30 for replacements (or tell them; that would be nicer).
*Note this definitely works for Intous4 because that's what I own. I'm 99% sure it works for the other models as they use the same nibs. But post here if you have another model and it works so we know for sure.