This app is great. I love the lifeline option. I love to hike but I have health issues. My family worries because I hike alone. Lifeline allows me to communicate to my chosen contacts my start time and estimated finish time. They can also track me on the trail real time. If something were to go wrong, they know exactly where I'm at. You can send messages in case your running behind schedule. The only problem I have is with the difficulty levels, totally inaccurate. Worth the money.