As this site likes to remind its readers, computer peripherals have the opportunity to greatly enhance or greatly frustrate our computing experience. Avoiding a few of these common pitfalls will help ensure you're in the former category -- not the latter.
1. Not Spending Enough
No, you don't need to break the bank when it comes to buying computer peripherals. But this is a category that is very much "you get what you pay for." Even though you can probably find a mouse in the dollar bins at your local discount store, it doesn't mean it's going to work very well or for very long. There's a happy medium for most people, and you'll eventually be thankful you didn't go on the cheap. Heavy computer users should consider durability and comfort to be of the utmost importance when choosing new peripherals. Your hands and wrists will thank you.
2. Not Doing Your Research
Don't buy a Bluetooth mouse if your computer doesn't have built-in Bluetooth. (Yes, you can buy an external dongle, but you're better off just sticking with another wireless device that comes with a nano receiver.) Don't buy a webcam if your laptop has one built-in and all you plan to do is Skype with Grandma. Figure out what you need, why you want it, and how much you're willing to spend. Then start reading the online reviews for any major red flags.
3. Not Backing Up Your Data
It is said time and time again on this site, but I still constantly speak with people who neglect to do even the most rudimentary backup efforts. Rather than harp once again, I will just leave you with a few of these links: