They last forever at home but at work they seem to run out at a fast rate and I have to search high and low for a new one because no one ordered any as usual.
Buying more won't help, whenever you really need a pen and your usual one isn't working, the only one you'll be able to find is a cheap minure one that probably came from a kid's birthday party 10 years ago. There's no way to avoid this, you just have to accept it.