Suppose Ford or Toyota would sell you a brand new car for, say, $500. Wow! Such a deal, you might think. But there'd be a catch: Every tank of gas would cost you $50, and you had to buy it from Ford or Toyota. Before long, you'd have spent a lot more on gas than you did on the car. \nThat's very much the situation facing consumers who use inkjet printers. The hardware is relatively cheap, but the cartridges are fairly expensive and they run dry fairly quickly, too. To save ink, you could print less or at a lower resolution, but why not do the same amount of printing at a lower cost and help the environment at the same time? That's the promise that vendors of remanufactured and refilled cartridges make. The question is, do they keep it? \nYou might expect me to say, "Remanufactured cartridges are a great idea\u2014nevermind warnings about poor quality from greedy printer makers. You'll never know the difference between the two." \nWell, I'm not going to say that. Last week I spoke to executives on both sides of the printer cartridge debate\u2014one with Hewlett-Packard, another with a company that makes refill equipment. They were easy to reach and seemed reasonably frank, considering both have skin in the game. \nMy conclusion: You can save as much as 50 percent with refilled cartridges and 10- to 20 percent with remanufactured cartridges. For many routine print jobs that's a perfectly acceptable solution. However, some print jobs won't look as good or last as long without fading. And there's a chance that a poorly refilled or remanufactured cartridge will fail, make a mess, and maybe even damage your printer. What about my warranty?\nYou may wonder if using a refilled or remanufactured cartridge will void your printer's warranty. No and yes is the answer, according to HP's Thom Brown, who carries the ungainly title of ink and media technology specialist. \nSimply using the cartridge does not void the warranty, he says. But\u2014and this is a pretty big loophole\u2014if the off-brand cartridge fails and damages the printer, you're not covered, he told me. \nLexmark's policy sounds similar: "Refilling the ink cartridges can cause them to leak, thus clogging or even damaging the print head. Any damage to your printer caused by refilled ink cartridges may not be covered under your warranty," the company says on its website. \nThe likelihood of buying a cartridge that wrecks your printer\u2014or at the least, simply doesn't work\u2014is hard to measure. Brown estimates that one in three refills don't perform as advertised. (He's not claiming that all of those will damage the printer.) \nMeanwhile, Bill McKenney, CEO of InkTec Zone, which makes equipment used to fill cartridges, says he's only come across one case in which a customer says his printer was wrecked and very few claims of defective refills. What about print quality?\nLike many technologies, inkjet printing is a lot more complex than it appears. Simply put, a cartridge holds a reservoir of ink which is heated to a boil by a heating element. The resulting bubbles spray through a gird of tiny holes onto the paper. \nThe exact composition of the ink determines the temperature at which it will boil, the size of the bubbles and how they flow though the holes in the print head. \nIn printer parlance, yield refers to the number of pages a cartridge will produce. Both sides agree that refilled cartridges tend to yield a bit less. In part, says McKenney, that's because a refilled cartridge may only hold about 95 percent as much ink as a new one. As cartridges are refilled multiple times, the yield will decrease a bit more. The average cartridge can be refilled at least three or four times before it is ready for the recycle bin. \nPrint quality, though, is a matter of debate. HP's Brown says the difference between the ink produced for his company and the less expensive brands used by McKenney's customers is substantial. "Ink isn't just ink," he says. \nHP formulates different inks for different types of printers and print jobs. Small variations in the formula can reduce print quality substantially, he says, and HP spends a good deal of time and money to get it right. Indeed, a newly designed cartridge and its ink go through as many as 1,000 iterations before a design is finalized, says Brown. \nMcKenney concedes that off-brand inks may not produce results that are as good as OEM inks for some higher-end applications, "but you'd need an awfully sharp eye to tell the difference," he says. \nTwo years ago, PCWorld (CIO.com's sister publication) lab tested new and refilled cartridges and found "that third-party ink cartridges usually cost less and often yielded more prints than their manufacturer-made rivals. On the other hand, in most cases, we confirmed the printer manufacturers' claims that their own inks produce better-looking images." \nAs to the quality of the cartridges themselves, PCWorld's research "tended to corroborate the printer manufacturers' claims. Brand-name cartridges consistently installed and ran without a hitch, whereas some third-party supplies worked poorly or not at all," the magazine noted. \nThere you have it. If you want the very best quality and don't want to worry about potential damage to your printer, use the manufacturer's cartridges. But you'll probably be fine\u2014and have more money in your pocket\u2014if you choose to buy a refill. \nSan Francisco journalist Bill Snyder writes frequently about business and technology. He welcomes your comments and suggestions. Reach him at firstname.lastname@example.org.