Parker refills are expensive but easy to write on

If they are used for signatures (which they are intended for), they can last for several weeks or even longer

If you write 800 to 1,000 words every day, it will take up to a week

If you do a middle school student homework and take notes in class every day, it will be used up in 3 to 5 days

One refill can probably write ≤10,000 words