There are numerous of apps to support/ monitor your battery usage. All-in-one Toolbox and Security Master is my favorite... Make sure you aren't using quick charge, it weakens your battery gradually. I only use that for emergency only. Don't always be in low power mode, only be on it when you have no access to your charger... The Galaxy s8 may not improved their 3000mAH battery from the Galaxy s7, but they improved the durability drastically..