Having enough storage for all of your files is a bit like playing Whac-A-Mole: just as soon as you think you’ve got enough, new photos, videos, TV shows, or movies pop up, and once you think you’ve got enough space for those, even more appear. If you’re not careful, buying additional computer file storage can get pricey very quickly!

One of our favorite solutions for quickly adding more file storage space to any setup is a Seagate external drive. Seagate offers a full array of external storage solutions ranging from behemoth multi-drive units to less capacious, portable units that are ideal for expanding storage on gaming consoles or streaming boxes. The right drive for you will depend on how much space you need, how you’ll be using your drive, and how portable you need it to be.

Ready to find the perfect file storage companion? Here’s everything you need to know to find your perfect Seagate external drive, as well as some of our favorites.

Before you look at any specific models, answer these questions.

The most important question to ask yourself before you start shopping is how much file storage you need today, and how much extra space you’ll need for tomorrow. If you’re buying a faster solid-state drive (SSD), you’ll have to settle for less storage. If you’re buying an external hard drive with several terabytes of space, be prepared for file transfers to be a little slower. Our best advice: determine what your total data storage needs are today and buy a drive that’s at least 40% larger than that.

There are two types of external drives: the traditional hard drive, which is built with moving parts and has high capacity, and the solid-state drive (SSD), which is much faster, but typically only comes in smaller capacities. Hard drives wear out faster, but they’re more affordable and are ideal for backing up data, especially if you have a lot of large video files. On the other hand, an SSD may not hold as much, but it’s often your best best for situations where fast access to your data is critical, for example, if you’re planning to use it with a gaming console or streaming box.

If you plan on taking your external drive with you to places like work or class, you’ll want to get a Seagate external drive that uses an SSD: it’s much smaller and is powered by USB, so it’s easy to throw in your bag and take with you. (In contrast, external hard drives usually need to be plugged into the wall, and they include big, bulky cases that don’t really fit anywhere besides on a desk.)

As you’re comparing different Seagate external drives, keep these features on your radar.

All external drives use a standard USB cable to connect to your computer, but some include a dual USB cable, so they can also get power from your machine using a second USB port. That’s a lot handier than having to find a wall outlet to plug your external drive into, although it can eat up your machine’s USB ports quickly. As you’re comparing models, consider how they’re powered.

Most Seagate external drives connect to your computer using USB ports: the rectangular ports that are just about everywhere. However, a new standard of USB is available: USB-C, also known as USB 3.1, which has a completely new form factor. USB-C is faster than traditional USB, and it can conduct both data and power without breaking a sweat, so it’s definitely worth the upgrade if your computer has a spare USB-C port.

Q. How long does an external drive typically last?

A. It depends on how often you use it and what you use it for. If you’re using your external drive for high-intensity tasks on a daily basis, it will easily last a few years before starting to show signs of slowing down. If you don’t use it very often, it can last for years longer than that. Just be sure to connect it to your computer on a regular basis to check to make sure it powers on and still has your files.

Q. How often should I back up files from my computer to an external drive?

A. It depends on how frequently you make changes to local files on your computer. For example, if your job or school requires you to create multiple new documents each week, a weekly backup will ensure that you never lose more than seven days of your files. On the other hand, if you don’t do a lot of your work locally on your computer and most of your newer files are in the cloud, you can get away with monthly or even quarterly backups.

Q. Can I connect multiple external drives together to transfer files between them?

A. No. External drives are designed to be connected to a computer via USB cable and aren’t able to connect to one another. If you need to transfer content from one external drive to another, you’ll need to use a laptop or desktop computer to connect to them both.