Hertz (Hz) is a scientific unit designating the frequency of an electrical event. Applied to televisions, hertz represents the per-second refresh rate of the display. The most common hertz value for televisions is 60 Hz, which means the set displays a new image 60 times a second. Generally, higher hertz values mean cleaner, smoother images on an HDTV. Factors that determine the appropriate hertz value for your needs include price, input and expandability.
Choose the right television for your requirements based, in part, on the type of inputs you'll need. If you watch high-definition sports or Blu-ray movies, you'll likely notice the smoother operation of a 120 Hz screen. If you watch standard-definition cable, over-the-air TV signals or DVDs, your inputs cannot take advantage of more than 60 Hz so there's no point in paying more for a TV with a 120 Hz refresh rate.
Choose the right television based on your budget. A 120 Hz TV will be considerably more expensive than a 60 Hz model, at the time this article was written. For a 42-inch HDTV, you'll pay $200 to 300 more for a superior screen refresh rate. The question to consider is not whether a 120 Hz screen is better (it is), but whether the additional expense is justified. Before deciding, check out televisions at your local electronics store and compare the movement and clarity of various screens, noting the price differences.
Choose the right television based on the additional factor of what upgrade options are available. Even if you only use standard-definition media presently, you may purchase higher quality cable/satellite options in the future. It's also possible that you might buy a new TV in a few years, and $200 or so saved now can be put toward a better television later, perhaps with a 240 Hz screen. Keep in mind that much of the current 3-D content requires at least a 120 Hz screen.