Ports and Expandability
Every computer user is familiar with the USB port, but not everyone is aware that a much faster update to the standard, USB 3.0, is slowly spreading through the computer industry. USB 3.0 can be 10 times faster than its predecessor in real-world usage, delivering transfer speeds of up to 400 megabytes per second [source: EverythingUSB]. Even if you don't own any USB 3.0 hardware right now, consider future proofing when buying a new laptop. You might be really thankful you have that USB 3.0 port down the road.
There are other ports to consider as well. Do you want HDMI to output video to a TV? Do you need an SD card slot for downloading digital camera photos to your laptop? Will you need an Ethernet port for Internet or will a laptop's built-in WiFi connection be enough?
If you plan on keeping a laptop for several years, learn how customizable or expandable it is. For example, Apple's laptops are known for their build quality -- and for being locked down and difficult to perform maintenance on. The batteries are integrated, rather than removable. Many PCs have removable batteries that can easily be swapped out or replaced.
Google your laptop to see if owners have found it easy to add additional RAM or swap out the hard drive. Either of those upgrades could give your laptop an extended lease on life sometime down the road, but some casings are much easier to open up than others. On a similar note, some laptops are especially designed to keep your data more secure. That's our next topic.