Waiting until devices reach 0% before charging them can actually harm their batteries in the long run. This is especially true for modern devices like smartphones, laptops, smartwatches, and wireless earbuds. Repeatedly letting a battery drain completely can reduce its overall lifespan, as it causes unnecessary stress on the battery cells. This habit was more common in the 1990s and 2000s, when devices used nickel-based batteries, which required full discharges to maintain their maximum capacity. However, modern devices use lithium-ion batteries, which behave differently and are more sensitive to extreme conditions. Lithium-ion batteries should not be left to drop below 20%, as doing so can cause a sharp drop in voltage, leading to mechanical stress on the battery’s internal components and accelerating wear. Similarly, charging a lithium-ion battery all the way to 100% is not ideal, as it exposes the battery to the highest electrical voltage and generates heat, which can also damage the cells over time. Constantly moving between the extremes of 0% and 100% puts the battery through the most stressful chemical conditions, shortening its life. To help preserve battery health, experts recommend following the 20-80% rule. This means charging the device when the battery reaches around 20% and unplugging it when it reaches about 80%. This range minimizes internal stress and keeps the battery in a more stable condition. Additionally, taking frequent, short charges throughout the day—such as charging for 10 to 20 minutes—is healthier than waiting until the battery is completely drained and then charging it all the way to 100%. This approach avoids forcing the battery into the two most stressful charge ranges. Many modern operating systems, such as those found in iOS, Android, macOS, and Windows, include features designed to optimize battery health. These systems learn from user behavior and can delay charging beyond 80% to prevent overheating. They then complete the charge to 100% just before the user typically wakes up or leaves for the day. These features help reduce the strain on the battery and prolong its overall lifespan.