I used a fountain pen all through school, from the age of about 8 to 16. For the vast majority of this time I used a single pen, a very cheap one (I think it was a pack of two or three for about £2). Since I'd used it so much at a slightly odd angle, the nib wore right down and I was so used to it that if it ever broke I'd take ages to get used to a new one.

I ended up dropping out of school at 16 and I never went back to collect my stuff, so that pen's final resting place is unknown. I've not used a fountain pen since. In university, I decided on a whim to start writing exclusively with mechanical pencils, and I really like them to casually write with. I have a fancy steel Parker mechanical pencil I was given as a gift and that's my main writing tool.