Personal computers can help us a great deal. They can do a fair amount of harm too, if we’re not careful. The trick is you have to use the technology—you can’t let it use you.

PCs can help in lots of ways. A PC lets you communicate more efficiently than a typewriter or telephone. It helps you plan and budget more effectively than a calculator or table. It makes it possible to keep track of people and things more easily than a roster or list. It can gain you access to more research than the largest collection of periodicals or books. And it makes training more compelling than words and pictures naked on the page.

In short, if you’re not so smart, PCs can make you look smart, and if you are smart, they can make you look smarter.

PCs can also hurt in lots of ways if you’re not smart in using them. They can hurt psychologically, socially, and physically. People can and do become “addicted” to PCs and digital devices such as smartphones and tablets, becoming too dependent on them.

One key test is whether your use of this technology improves the overall quality of your work, school, or personal life—or degrades it. Just as overdoing activities such as shopping, being a sports fan, gambling, and much else can cause you to lose a job or partner, so can overuse of PCs and devices.

In young people, overreliance on digital devices can also hamper social development. When there’s an easy social “hit” from your device or PC, this can cause you to be by yourself too much, preventing the full development of in-person social skills.

PCs and devices can hurt the social lives of adults as well. In her book Alone Together: Why We Expect More From Technology and Less From Each Other, MIT psychologist Sherry Turkle writes that electronic communication for some can compromise the ability of having a real conversation and to reflect when you’re alone. Turkle believes that we’re giving human qualities to our devices, and that we’re treating each other as things.

PCs can also hurt us physically, and this goes beyond getting hit by one when someone throws theirs out the window in frustration. Whether you’re using a desktop or laptop PC, you typically use it while remaining relatively stationary, and not moving can cause problems. So can doing the same movement repeatedly for long periods. Both situations can lead to repetitive stress on wrists, shoulders, necks, and backs and to potentially painful and debilitating conditions.

The simple act of sitting for too long, whether at a PC or not, can cause problems. According to a study by Australia’s Sax Institute (45andup.org.au), people older than 45 who sit for more than 11 hours a day are 40% more likely to die within three years and those who sit between 8 to 11 hours a day are 15% more likely, compared with those who sit less than 4 hours a day. Other researchers have found that physical inactivity increases the risks of heart disease, cancer, diabetes, and back and neck problems.

To avoid problems from sitting, some people work at their computing while standing up. You have various options here. A height-adjustable desk, sometimes called a height-adjustable workstation, a hi-lo desk, or an ergonomic desk, can be adjusted to use when standing or sitting. They cost from several hundred to several thousand dollars.

A standing desk, also called a stand-up desk, lets you work only standing up. With a laptop, you can use a podium for this purpose. 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. A Parsons End Table from Walmart costs just $12 and works well.

But a new study by the Human Factors and Ergonomics Society (eurekalert.org/pub_releases/2015-07/hfae-lss071315.php) shows that standing in one place for too long can cause bone and muscle damage. Common problems faced by police officers, security guards, and others who have to stand in place include heel spurs and plantar fasciitis.

Some people use a treadmill workstation, where you walk while you work on a PC, either a ready-made version or one they put together themselves. But working like this, according to some, can compromise concentration.

Perhaps the best solution is to simply take breaks. Stop what you’re doing every half hour or so and do something else, even if it’s just walking around or stretching.