If you're going to take on video projects, you have to be ready to handle them. And by handle them, we mean have the storage space to accommodate the large files that will undoubtedly come with it all.
Video files are large, and there's no getting around it. The higher the quality, the larger the file size. A 1080p HD movie file size is typically 8-15 gigabytes, and can skew larger or smaller depending on the file type. You will need a hard drive that can store all that and more, or you'll find yourself quickly running out of space.
But it's not just hard drive space that you need. You also need the RAM (random access memory) built into your computer that can handle all the rendering that comes with editing video. When you edit video, there are often many layers--effects, shots, audio--and all those layers need to be smooshed into one—in other words, rendered into a finished product. That creates a lot of temporary files that take up a lot of space. More RAM means faster rendering. More RAM is more expensive, and depending on what kind of computer you're using, adding RAM after the fact may be prohibitively expensive, or even impossible.
So, what should you look for?
You will want at least one external hard drive of 500 gigabytes or more. Reliable brands start at about 50 dollars. The virtue of an external hard drive as well is that you can take it from computer to computer, allowing for a more mobile experience. It also takes the stress off any one computer, and prevent a loss of files if a computer crashes. If you're not editing video—let’s say you're an actor with a bunch of clips and demos you're storing—having that external hard drive makes it easier for you to have those files at your fingertips when you are marketing yourself on the road or around town.
RAM is not as essential for an actor looking to store video clips. But for editors, the more RAM the better. A good benchmark is 8 gigabytes of RAM for basic video editing and effects. For anything more advanced, 16 gigabytes or even 32 becomes more appropriate. Prior to making a decision on how much RAM you'll get, make sure you have a realistic evaluation of the amount of video work you'll be doing. Also note whether your computer can handle more than eight gigs of RAM. If it can't support more RAM and your video projects are ramping up, you may have to consider upgrading your whole system.
That said, external hard drives and RAM are great investments, and worth as much in many ways as an investment in shooting equipment or headshots.