What should I know about using refilled print cartridges?

While Hewlett-Packard does not prohibit the use of refilled print cartridges during the warranty period, it is not recommended. Repairs resulting from the use of refilled cartridges are not covered under Hewlett-Packard warranty or maintenance contracts. HP has no control to ensure that a refilled cartridge functions at high reliability levels or to predict long-term reliability effects on the product.