You're wise to worry about repetitive strain injury (RSI), which afflicts many computer users. From sore wrists to tight shoulders, long-term computer use does come with some physical risks.

To stave off injuries, first make sure your family members know how to adjust the computer monitor to the right height for them -- the top of the computer screen should be around eye-level. The monitor should also be about arms-length away. This prevents eye-strain and limits you from craning your neck too much.

To protect your wrists, think about installing an adjustable keyboard tray that each person in your family can raise or lower to make sure their elbows are at the recommended 90-degree angle when they're typing. But the best way to prevent injuries is to take breaks from typing at least every half hour to stretch.