Never had that problem. I always hear people touting that but it's never happened to me personally. I have ink in bottles for years that still works same as it ever did.
Though inks have expiration dates, they generally don't matter. I just installed some ink that expired in 2009 in my Epson Stylus Pro 3880 and it works great.
"Ink in bottles" or old ink isn't what the person you responded to was talking about though. It's residual ink inside the print head and exposed to air. For most ink jet printers you will get clogged nozzles if you don't print once a month or even more frequently with some printers. Having a few lines in your papers may not bother you if you are just printing memos or instructions and you may not even notice, but it can ruin a photograph with expensive ink and photo paper.
For older two-cartridge printers where the print heads were built into the cartridges you would just buy new carts but this made the carts even more expensive and wasteful (toss all three colors just because you ran out of one in your color cart, for example). I remember being stingy with my first inkjet printer in 1997 specifically because the replacement carts were so expensive. It was a Lexmark and, sure enough, most nozzles were clogged when I went to print almost a year later. In my attempt to save on replacement cartridges I ended up ruining my carts!
I recently got an HP OfficeJet 7000 Wide Format E809a printer from Goodwill and, sure enough, the printhead has some clogged nozzles that ruin photographic output. Was hoping to get lucky and get a decent wide format photo printer for cheap. That one was $6 and luckily a replacement printhead is $20 (most photo printers will be over $100 and impossible to self-install). Before I could get one, however, I came across that Pro 3880 for $10 (another Goodwill find).

This one leaks Photo Black but works fine when you switch to Matte Black. All nozzles firing (*whew*).
Canon Pixma printers are known for performing "maintenance" every 48 or 72 hours or something if not being used. This uses a bit of ink but keeps the nozzles from clogging. If it runs out of ink or you leave it unplugged or it can't do its thing for some reason or another, it will clog too. It still happens and this is why people are buying the $60 Pixma Pro-100 just to sell the printhead for $125 (well, the ink is also worth that and the included paper details for $40). Pretty sweet deal if you can stomach the $250 rebate!