With more than 50 percent of Americans using smartphones, one of the biggest environmental hazards comes from the millions of rechargeable batteries that need to be replaced and disposed of every year. One way to help is to conserve battery power whenever possible. According to Blackberry, one mistake most smartphone users make is turn off Wi-Fi when not in use thinking it improves battery life. You should keep it on -- when you do connect to a Wi-Fi network, it offers substantial power savings. Make sure you are adding Wi-Fi networks and hotspots to your phone so you can take advantage of this whenever possible.