Personally I am not the type of consumer that like to register my electronics and software unless I need to in order to "activate" the software. So it comes to no surprise that I never registered the 20 or so printers I used at home in the last 15 years. Each year I would wait toward "Black Friday", which is usually the day after Thanksgiving to go to stores like Fry's, Office Depot, Staples, and get "disposable printers", where they cost less than $20 or even free. These are great for letting the kids print or as a backup. When the ink runs out, it is much easier to dispose of the printer by taking to the nearest electronic recycle event than to buy refill inks because the ink would cost you about $50 for a $20 printer.
For more higher end use, I would usually buy the $300 and up printers. Usually the Fry's, Office Depot, etc. would try to sell you the warranty, which is usually 25% of the printer's price for 2 years and about 33% for 5 years. Their biggest selling point is the convience of bringing them the printer when you have problems instead of sending it out to the printer manufacturer and waiting for them to fix it or send you a new printer, when you can borrow a loaner from Fry's.
Almost all of my printers are Epson. Reason is because I am pretty happy with their products and want to keep similar models around so it is easier to maintain. Most printer companies would give you a 1 year Manfuacture warranty, but didn't realize just recently that Epson would extend your printer warranty to 2 years if you registered with them online. Not a bad deal since just last month two of my Epson Workforce 600 had issues printing black even after changing to new ink cartridges. The tech support wait was about 1 minute and they send me a new printer (actually a remanufactured printer, which is a printer that used to have problem but was fixed) and included a label to return it via FedEx.
My advise is that if you have an Epson printer, look into having it register to extend your warranty. If you have other brands, it might make sense to know what is your warranty. And always check the manufacturer warranty before shelling out for the extended warranty from the stores. It might be worth to spend $40 for it now and save yourself from spending $150+ to fix it if your printer is out of warranty.