Fountain pens! God, I forgot about them. My primary school (ages 4-12) insisted we use them, though I can't remember at what age we started using them. I remember, unlike everyone else, I was able to use the same fountain pen throughout my time at the school. Biros were forbidden, and if you got caught using them you'd get in trouble. Keep in mind this was 80's Ireland and the school was run by the church. The remaining nuns were ageing and half the teaching staff were not a part of the church.
The nuns lived in a convent next to the church just down the road, and they had orphans being taken care of. One of them was in our class, and she was always short of cartridges for her fountain pen, so she was always borrowing them. I remember the principal (a nun, naturally) found out, bought a large box of cartridges and frogmarched her down to the class where it was announced that she would give everyone back what was owed. I'll never forget the look on the poor girl's face as she went around person to person.
Everyone was always wanting for cartridges, since we were usually writing all day long. It's been many years since I've used one. I remember them being quite messy, at least in our young hands. Secondary school (ages 13-18) used biro pens which was a godsend - you could write much faster with them. Of course that just meant people kept running out of ink and needed new pens constantly.