Yes. You can reuse a cartridge if you sanitize it properly after each session (soak the head in 70% isopropyl alcohol for 10 minutes, then air-dry needles-up).
The needle cartridge can be used up to a month if properly cleaned after each use. Over time, the needle head may become blunt and, if not cleaned thoroughly, unsanitary. For this reason, many customers prefer to replace cartridges after 3 uses for maximum effectiveness and safety.
If you’d like extra cartridges, you can purchase them here: