One of the things I learned a long time ago was that optical drives, CD, DVD, and MO, go wonky much more quickly than any other component of your computer or audio/video system. On every Mac I've owned the CD-ROM drive has developed difficulty reading discs within two years. This usually starts with the disc whirring and repeatedly rotating until it either mounts the disc, stops attempting to try to read it, or spits it out.
At my former office, we used magnetic-optical discs for back-up and one of our MO drives was crapping out. A programmer who temporarily worked at our office and who claimed to know a bit about the mechanisms in optical drives told us that this sort of failure is inevitable and that most of them weren't going to go the distance because the optical mechanism wore out rather quickly. He said that it was almost certainly going to start experiencing problems after 4 years and often has issues sooner than that.
I don't know if this fellow knew what he was on about but the information he gave me certainly fits in with my experiences. Knowing this, I've made it a habit to replace failed internal DVD and CD drives on computers with the cheapest possible solution. The same goes for the DVD player we connect to the television. Getting a high-end solution seems pretty pointless when there's a decent chance it'll crap out in 3 years or so. Of course, there are people who are dead certain that the DVD media is dead and have already concluded that CDs are ancient technology. Nonetheless, I still continue to need mine and to find that software is distributed on them.
My husband uses his notebook PC (an Acer) in his English lessons with his students for a variety of purposes. One of the things he does sometimes is watch DVDs that his students want to discuss the contents of in class. This actually allows him to teach the types of classes that other teachers envy, but it also means he needs a PC with a functioning DVD drive as PCs are not part of the standard classroom equipment. When his DVD drive started having difficulty reading one of his student's DVDs, we knew it'd have to be replaced.
While I was researching replacements, I discovered that the model used in his Acer was troublesome for many users of that particular drive. I also discovered that it cost around $200 to buy a new one and the known issues with it meant that a replacement wouldn't necessarily work any better than his currently faulty one. Given these problems, we decided to go for a portable external DVD drive to replace my husband's ailing internal mechanism. As always, I check Amazon in the U.S. first for a baseline price for various models then check Amazon Japan for the same models if they are available to see how much more expensive they are here. If the price difference is too great, we have family ship a U.S. model to us. If it's a reasonable gap, we just buy one here.
The baseline model for me was a nice portable Sony dual layer DVD burner/player for about $96. It was compact, had a USB2 connection, and could burn and read almost any type of disc. The price was also quite reasonable. Unfortunately, Amazon Japan didn't carry it and most comparable models were about $180.
Fortunately, continued poking around in the electronics section at Amazon Japan turned up a Buffalo model which had everything the Sony had for only about $20 more. Buffalo in Japan seems to be the low cost model for almost anything you want as a peripheral for a computer. I'm guessing it might be regarded as a relatively undesirable brand but I've had pretty good luck with all the Buffalo items I've purchased among which there have been two high capacity hard drives, a Firewire PCI card, and a PC slot LAN card. None of these items have ever failed though I did drop and destroy one of the hard drives though I can hardly blame Buffalo for my clumsiness.
The drive is only slightly larger than a CD jewel case and brings to mind the old IBM external floppy drive mechanisms I used to see people using at work as companions to their ThinkPads ages ago. It has an AC adapter but also runs off of USB bus power. I tested it out on my Mac Mini (which cannot power anything which runs off the bus except thumb drives and required the AC adapter) and on my PC (which did run it off the bus only) and it was instantly recognized and worked fine on both without any driver installation.
Since my husband is very hard on his hardware and he'll be tossing this drive into his backpack when he goes to work, I decided to track down a case for it. I've found that the Daiso 100 yen shop has a wide variety of such things and sifting through the copious number of cases yielded one which was not only a perfect fit but also has a zippered pocket on the outside for the USB cable.
Word is that the next super small models of Macs will come without a DVD drive and I'm thinking that something like this should be very handy to have around should that time come and should I take the plunge on a new Mac. In fact, given my problems with internal drives, I find this a preferable option.