I have always advised people to research and read reviews before buying any stuff. Plenty of user reviews are available on the Internet, written in blogs, websites and forums. Read them and know what previous customers and users have to say about the product, what's good and what's bad about it. Know thoroughly what you are going to buy so that you don't end up making the wrong decision.
Apart from reading reviews, another effective way of getting a first hand impression of the product is by reading it's manual. At Diplodocs you will find over a million manuals for thousands of products in 26 different languages. From DVD players to home theatres; from washing machine to air conditioner, you will get manuals for a wide variety of products and appliances.
These manuals are free to download and so you get the chance to read the manual before you actually buy the product. These gives you a great opportunity to do your own research rather than relying upon reviews written by other people. Is an appliance as easy to configure as advertised? Is it easy or far too complicated? Does it have the necessary features you are looking for? How much power does it consume? You will get detailed information and features of the product that often reviewers forget to mention in the manual. All this will help you to make a better buying decision. And if you already own a product but have lost the manual, you know where to find it.