The use you make of your home or office printer will determine how often you need to replace the ink cartridges. The more colour printing you do, the more often the cartridges will need replacing. Don't forget, though, that black-only printing still requires all four colour cartridges to be functional. Printer manufacturers always tell you that only cartridges supplied by them will provide satisfactory results. This is not necessarily the case, as tests have shown that refilled cartridges are perfectly adequate. They can be obtained from specialist suppliers or you can refill the cartridges yourself. When you search for office supplies you will find a variety of ink cartridges offered. 'Genuine original' cartridges are straight from the manufacturer and expensive. 'Compatible' or 'generic' cartridges are not a known brand but made to suit different printers. If 'manufacturer refurbished' they are refilled by the original maker. 'Refilled', will be cartridges with the ink replaced. These should have been properly cleaned before refilling. Not surprisingly, it's easiest to buy refilled cartridges for the most popular printers. HP, Canon and Epson are all very well supported. Apple, Brother, Lexmark, Panasonic, Kodak and Dell are just some of the other printers with refilled cartridges. So long as you know the exact type of cartridge you require, you can search for a refilled version. Before changing your printer, it may be worthwhile checking that refilled cartridges are readily available for it, as it could save you a lot of money. It's generally accepted that you can save up to 80% on your printer ink costs by buying refilled cartridges. Just to give one example, a full set of Epson cartridges that would cost A�32.89 from Amazon at a discounted price can cost half that from a reputable dealer. Where to look for these vital office supplies? Cartridge World has an excellent reputation and provides cartridges for a very wide range of printers. The Ink Factory is also recommended. eBay now has many professional business sellers and is another good source. You may notice there that some cartridges are listed as 'seller refurbished', in which case it's worth looking at the seller's feedback to check their reliability. If you decide to take the DIY route there is plenty of help available online and you can find detailed instructions on how to refill your own cartridges. The important thing here is to know the model of your printer and the cartridge number (it's a good idea to preserve the old packaging) to ensure that you buy the right ink for your printer.