Closing background applications on a smartphone to save battery life is a common belief, but it is actually counterproductive. Background apps do not consume energy as they are frozen in the memory (RAM) and their processes are suspended. Forcing their closure empties the RAM, requiring the smartphone to reload everything upon reopening, which leads to increased electricity consumption. The only justified case for forced closure is when an application crashes. Leaving Bluetooth activated is often believed to drain the battery rapidly, but this is largely a remnant of older technology. Modern smartphones use Bluetooth Low Energy (BLE) standards, which consume minimal power in standby mode, typically around 1 to 2% of the battery on a full day. Manually disabling Bluetooth only provides a minimal gain in battery life and can limit useful features such as synchronization with a connected watch or instant connection to headphones. Using a more powerful or third-party charger can be a concern for battery health, but smartphones are designed to request only the power they need. Standardized protocols like USB Power Delivery (USB-PD) ensure that the charger and the phone's power management chip communicate before sending power. Therefore, using a higher wattage charger than needed is generally safe, provided the charger meets basic safety standards such as the CE marking. The real risk comes from low-quality chargers or cables sold without proper safety compliance. Leaving a smartphone charging all night is often considered harmful, but modern devices have built-in systems that regulate the electrical flow. Once the battery reaches 100%, the phone switches to a maintenance charge to prevent overcharging. Additionally, iOS and Android include optimized charging features that delay full charging until the user typically wakes up, reducing chemical stress on the battery. However, it is important to avoid overheating by not covering the phone while charging. Airplane mode is not limited to use during flights. It can be useful on the ground by cutting off all wireless communication, which helps reset network connections, conserve battery in areas with poor coverage, and speed up charging by reducing passive consumption. Restarting a smartphone is often seen as unnecessary, but it can help reset the system, clear memory, and stop background processes that may cause the device to slow down or overheat. Restarting the phone once a week is recommended to maintain its performance. Blue light filters are often believed to improve sleep quality by reducing blue light exposure, but their effectiveness is limited. While they can reduce screen brightness and improve reading comfort in the dark, they do not eliminate the overall brightness that affects melatonin production. The actual activity on the screen, such as scrolling through social media or watching videos, is more impactful on sleep than the color of the light. The belief that smartphones listen to conversations to target advertising is a common concern, but in practice, such continuous listening would drain the battery and trigger microphone access indicators on iOS and Android. Instead, advertising algorithms use real-time data such as geolocation, search history, and browsing habits to create targeted ads.