How long a refill lasts depends on individual writing style: on average a roller refill with a 0.5 mm tip writes for 800 meters, while a refill with a 0.7 mm tip writes for 450 meters. Ballpoints last much longer: the 1 mm tip writes for approximately 3500 meters. We suggest using the refill within 24 months of purchase. After 24 months the ink starts to evaporate.