Washingto - Many people today rely as much on their smartphones as they do on their computers. So questions about how best to use smartphones, how to make them last longer on a charge, and how to protect them are common. Read on for some answers.

Q: My smartphone has Wi-Fi, but I never use it. When should I use it?

A: More phones today offer Wi-Fi connectivity, which essentially allows you to use local Wi-Fi hotspots - either public or private - to wirelessly connect to the internet.

This service allows one to skip use of the 3G or other network provided by your cell carrier to surf the Web, send and receive e- mail, make voice over IP (VOIP) phone calls, and more. There are both advantages and disadvantages to using Wi-Fi.

First, Wi-Fi can save you money. Unless you have an unlimited data plan with your wireless carrier, you're only allowed to send and receive a certain amount of data. Using Wi-Fi rather than your carrier's network allows you to skirt any data cap while still being able to access the data you need.

Second, Wi-Fi access speeds may be more robust than the network connection provided by your carrier, which can translate into faster Web-enabled application performance. Third, Wi-Fi may provide you with data coverage where your wireless carrier's network signal is weak.

Wi-Fi is, in short, another option for accessing data that may be both cheaper and more reliable than your default network.

Engaging your phone's Wi-Fi capability may, unfortunately, result in shorter battery life, since the internal Wi-Fi chips themselves require additional power. Turning Wi-Fi off when you don't need it should extend your phone's battery life, which of course can be critical on the road. Accessing data over Wi-Fi may also not provide the level of security you require.

The best way for you to determine the overall advantages versus disadvantages of Wi-Fi is to activate it within your phone and try it out.

Q: How can I make my phone's battery last longer per charge?

A: If your mobile phone or smartphone offers a "standby" mode, use it. Standby mode puts the phone in a lower-power state while still keeping it ready to receive incoming calls and text messages.

This mode is more power-conserving than any standard "lock" mode, which simply prevents keys from accidentally being pressed. Also, de- activate any of your phone's features that you aren't using, including Wi-Fi and Bluetooth.

Turning your phone off will, of course, be the best way to preserve battery life, but that tactic is useful only if you do not need to be notified instantly of incoming messages or calls. You turn most phones off by holding down the "call end" key for a number of seconds. Typically, you turn the phone on again by holding down the same key.

Battery life becomes an issue as your phone gets older. Mobile phone batteries do wear out. Many claim their useful life is just one year.

After that, the phones will require charging more often than they did when the battery was new. Replacing the battery when you notice consistently less up time per charge is a good strategy, but cell phone batteries are not inexpensive. Try looking for replacement batteries on eBay or at discount electronics stores, rather than the store from which you received the cell phone itself.

Q: I keep getting unsolicited text messages. How can I stop these?

A: These are annoying indeed. Obviously some company that sends out unsolicited text messages has gotten your telephone number. The overwhelming feelings of those who receive these messages are anger and powerlessness, but be careful that the actions you take in retaliation do not end up making the situation worse.

Do not, for example, call the number from which the unwanted message came. Doing so will likely just result in a fee for calling an out-of-area number.

Instead, first call your wireless carrier to ensure that you are taken off any marketing lists that they may have, and ensure that your number is not given out or sold.

Also, you probably have the ability to block particular numbers, either through a message setting on your telephone or through your wireless carrier. Inquire with the carrier about how to block any such number. You can also try texting the words STOP or UNSUBSCRIBE in response to the unwanted text message you received.

Q: I want to protect my smartphone's screen. Which protector should I use?

A: Smartphones aren't exactly inexpensive, even when purchased as part of a wireless plan, so it's natural to want to keep them looking good. Invisible Shield (http://www.zagg.com) is a clear protector favoured by many who want to keep the LCD on their phones scratch- free.

OtterBox (http://www.otterbox.com) makes a popular series of shells that will protect the rest of the phone. You might be surprised, however, at just how tough the casings and the LCDs of current-generations phones are. Many people have learned that no protetction is needed if the devices are treated with reasonable care. (dpa)