This ars technica article is a bit older but probably none the less applicable. The gist of it is that inkjet printers claim that a cartridge is empty much too early. If you replace right then, you may be paying twice as much as necessary depending on your printer model. And that does not given count the ink lost to nozzle cleaning and the like.
In the days when I had an inkjet printer, first an HP, then an Epson Stylus Color, I was frequently frustrated by how short the cartridges lasted and by how much they were to replace. On top of that, my Epson printer would frequently dry up because I used it only infrequently, causing it to go through a lengthy and noisy (and presumably ink wasting) cleaning cycle.
Like most level indicators those on inkjet printers are apparently not very good. With rechargeable batteries, indicators usually go off too late, giving all but a couple of minutes until the battery dies. A happy medium appears hard to come by. At least in the case of batteries it doesn’t cost you money.
Myself, I already 4 years ago decided that I had had enough of inkjet printers and bought an entry level laser printer (HP LaserJet 1012) with which I am extremely happy. It starts up almost instantly, prints much faster than an inkjet and obviously at a much better quality. I don’t mind that it is black and white, I rarely have a reason to print in color. At ~$60, the cartridge costs approximately the same as an inkjet cartridge but lasts much longer and never dries up.