When is the best time to refill my inkjet cartridges? Customer Service Updated April 01, 2019 17:27 If possible, you should refill your inkjet cartridges before they run out. This will prevent ink from drying in the print head between refills. Related articles How many times can I refill a cartridge? How do I use a refill kit? What are inkjet refill kits and how can they save me money? The Differences Between OEM, Remanufactured and Compatible Printer Cartridges Can I refill a toner cartridge?