Many of your apps work -- or work better -- because of Location Services: maps, navigation, search, weather, ride services, photo geotagging, social media check-ins, and so on. However, you may also find Location Services invasive: burning up battery life, targeting you with local ads, or letting apps track you when you don't need or want them to. Uber, for example, has gotten flak for accessing users' location even when they're not using the app (it also wants to mine your address book). Find out how Location Services works, its pros and cons, and how to enable or disable it.
How Location Services works
Location Services enables native apps (like iOS's Maps, Weather, and Clock), third-party apps (Uber, Waze, MapMyRun), and system services (Compass Calibration, Location-Based Alerts, Setting Time Zones) to use local cellular, Wi-Fi, Bluetooth, GPS, and cell tower location data to tailor what they display by tracking your whereabouts.
Why not use GPS alone? GPS uses satellites, works better outdoors, and is more accurate. Using a combination of cell towers and Wi-Fi signals makes for less accurate pinpointing, but the method works both indoors and out and uses far less power, which is kinder to your phone's battery.
Benefits of Location Services
Location Services helps companies like Apple and Google, which may in turn help you. They can learn which apps are most geographically relevant to people in your area and thus give better recommendations. They can track all the places you've recently visited for improved predictive traffic routing. And they can provide geographically relevant search results and ads. Location info is also used to compile a crowdsourced database of Wi-Fi hotspots and cell tower locations, so you can find a connection more quickly. Should you lose your iPhone or Android phone, Find My iPhone and Android Device Manager rely on access to your device's location in order to track it.
Here are some examples of how popular iPhone and Android apps use your location information:
Downsides of location sharing
While Location Services has its perks, there are downsides. First, your battery will drain faster with Location Services running in the background.
Second, you may not feel comfortable with certain apps tracking, storing, or sharing your location info. Check the app's policies on privacy, data retention, ads, and sharing info with third parties.
Third, having your location monitored comes with some privacy and security risks. If your posts or photos are geotagged, then anyone (friends, frenemies, and even strangers, if your posts are public) can find you at any given moment. Knowing where you are can also be advantageous to criminals. If you're posting photos from your tropical vacation, social media-savvy burglars now know that your home may be left unguarded.
How to enable or disable Location Services
For iPhone and iPad
Go to Settings, Privacy, then Location Services. You can switch Location Services completely on or off, or you can tweak settings for each app, as well as for system services like Compass Calibration and Setting Time Zone.
You can also look there to find out which apps have recently used your location and whether the apps use your location always, only while using them, or never. Under Settings -> Privacy -> Location Services -> System Services, you'll find Frequent Locations. Scroll down to the History section and uncover a list of places where you've spent the most time over the past month.
Head to Settings, then Location. You may see different choices, depending on your service and version of Android, but make sure that all options like Location, Location Services, and Location Reporting are selected. Then choose an accuracy setting -- pick one that includes GPS, Wi-Fi, and mobile networks.
To turn this feature off, open the App Drawer and then Settings. Tap Location, Google Location Settings, then Location Reporting and Location History, and toggle the slider to Off for each one. Delete your phone's location cache by clicking Delete Location History.
Whether you're on an iPhone or Android, in the event of an emergency, emergency services can still locate you -- even with your Location Services disabled. But if you want to locate a lost or stolen phone using Android Device Manager or Find My iPhone, you will have to at least temporarily enable your location services.