Personal computers, tablets, and other digital devices can’t kill you, except in extraordinary circumstances. One example might be a PC dropping on your head after someone threw it out of the window in frustration.

But any kind of digital device can hurt you if you don’t use it properly.

The culprit is typically a repetitive strain injury, sometimes called a cumulative trauma disorder, which can be caused by excessively repeating the same motion or non-motion. Because PCs and devices can be so captivating, spending a long time with them is common.

Whether you thumb type furiously at a smartphone or mouse your way around word processing documents and websites, whether you push a touchscreen on a tablet or sit in the same position in front of a laptop watching movies from Netflix, if you do it long enough, you put your body at risk.

Even if you haven’t yet experienced a sore wrist, shoulder, neck, back, or eyes, you should give some thought to how you position yourself. You don’t want to wind up in a situation where you can’t get yourself dressed, feed yourself, or hug your children, which does happen to some people.

Good ergonomic equipment helps, but according to experts your work habits are just as important.

Some feel that the best thing you can do for your health around computers and digital devices is to stop using them, though this of course is impractical for most people. At the least, take frequent breaks.

Gimme a Break and Auto Timer are free extensions to the Google Chrome and Mozilla Firefox web browsers respectively. Each periodically reminds you to take your eyes off the screen.

Alternately, you can buy an old-fashioned kitchen timer and set it to remind you to take breaks.

Another frequently repeated piece of advice is to listen to grandma: Posture counts. Sit in front of a desk whenever possible, which is better for your back and neck than sitting on a cushy sofa or lounge chair. While at the desk, sit up straight with shoulders and head back, feet flat on the floor or a footrest, and forearms parallel to the floor.

With a keyboard, the cardinal rule is: Try to keep your wrists straight to prevent wrist problems. With a mouse, try to keep it as close to the keyboard as possible, to prevent shoulder problems from having to reach for it. A touchpad built into a keyboard is even better.

If you use a desktop PC, don’t position the monitor too high. You should place it so that if you look straight ahead, you’re peering just over the top of the monitor. Then angle up the monitor slightly.

Ergonomic chairs that are adjustable in multiple ways can go a long way in preventing back problems. Recommended high-end brands include Aeron from Herman Miller, Leap from Steelcase, and BodyBilt by ErgoGenesis.

You can also find adjustable ergonomic office chairs at your local office supply store, such as Staples or OfficeMax, that range from pricey to affordable. Being able to sit in a chair, play with its controls, and evaluate the seat padding can help determine if that particular brand and model is right for you.

But sitting too long in even the best chairs can still lead to stiffness and other problems. Working while standing is a viable solution for some. Sitting/standing desks, also called height-adjustable desks, height-adjustable workstations, and hi-lo desks, cost from $300 for low-end manual adjust to $3,000 for high-end electric adjust.

Alternately, you can fashion your own set-up for under $25 by placing on top of a desk a small end table that’s big enough for a laptop or tablet.

Some intrepid users swear by treadmill desks, where you walk while working, whenever the mood strikes you. Here too you can buy or build yourself.

Eyes are another common sore point when computing. Experts say your most eye-friendly moves are to stay a foot and a half away from the monitor and minimize screen glare by positioning external lighting to the side, rather than in front or behind.

With your eyes also, you should periodically give it rest. Look away from the screen every 20 minutes or so for about 20 seconds, or close your eyes for the same amount of time.

Along with the above, stretching, exercise, and massage can help keep your body healthy.

Computers and other digital devices are great, when they’re not a pain in the neck, the back, the wrists, the eyes …