Even if you’re not in the market for a new TV, you might be wondering whether it’s time to change your TV service. Ads from cable, satellite, and phone companies promising more HD programming, improved picture quality, easy recording, and more could tempt you to upgrade your package or switch providers. Many TV-service providers boast of offering 100 to 150 HD channels, up from barely 20 channels a year or two ago. There’s no agreement on what constitutes a high-definition “channel,” so it’s hard to compare claims. Some providers classify each regional sports network feed as a channel, for example. It’s safe to say that all service providers have been adding more HD channels to remain competitive, but you’ll have to check to see what’s available in your market. The surge in HD is being driven largely by competition. As Verizon, AT&T, and others roll out fiber-optic networks that can handle TV, voice calls, and Internet access, more consumers have a choice of service providers. The telcos, as the phone companies are called, are expanding fast. Verizon was the top-scoring TV service provider of any type in a recent survey by the Consumer Reports National Research Center. Price, shop & save on cable/satellite plans If you want to sign up for HD or change providers, consider the following: Determine what’s available Cable is accessible in most parts of the country except for some rural regions. About 98 percent of markets are served by a single cable company, so you probably