When buying electronics, it's wise to do a lot of research beforehand. You should consider the longevity and durability of the product, how long before it's obsolete, how fast it will drop in price, and its compatibility with other products. By looking at these more, you're sure to make the best purchase.
Obsolescence is the most important thing to consider when looking at computer-related products, as that technology advances very quickly. For instance, MP3 players may only work with certain computer programs, so you'll want to know if your current hardware will be compatible with the next version of an operating system. The last thing you want is for an upgrade to the computer to render the MP3 software and player useless.
You should also look at compatibility issues. For instance, many students use word processing software, and when they decide to buy a new computer, they will want to know if its word processing software uses the same document formats (or at least the newer version is backwards-compatible) as their old papers, so that they can still get into all of their work. Furthermore, when buying a computer, it is often a good idea to aim for the top of the line, or close to it. True, it will cost more money, but that could mean the difference between a computer that has to be replaced in five years instead of three, once it becomes outdated. The extra money will be worth it.
It's a good idea to buy products with warranties, especially if they are brand new. Sometimes, first-generation products will have a number of bugs that were not caught in the initial testing process by the developing company. Check what the warranty covers, from water damage to factory damage. After all, there's no need to spend more money to replace a product when you don't have to.