I carry a fountain pen and a bottle of ink around with me (and some toilet paper to wipe the pen after filling). I've refilled on the bus, in other people's houses, in lectures and tutorials, all without making any more mess than sometimes some ink on my hands (but I don't mind if people think I'm an artist). Only once (eight years ago, almost to the day) did I have an accident, flooding my bag with ink just before an exam (the lid of my bottle of ink was not on properly).

Edit: And as for the pens themselves, I've used a mere four pretty basic Parker fountain pens during the last twenty years, two of which are still in service. Of the other two, one was broken by a classmate in high school messing around, and the other by me dropping it nib-down onto the floor.