Like any other portable computer device, a laptop has a built-in battery that will lose capacity over time, reducing battery life. Given that, it's possible that you're observing a decreased battery backup on your laptop before the battery is actually supposed to fail. When your laptop battery runs out too rapidly, you may find it annoying to have to keep looking for power outlets. Do not worry if you find yourself in this situation.
In rare cases, battery drain issues could be caused by outdated drivers and software. Keep your operating system and device drivers updated, since manufacturers routinely provide updates that bring improvements and problem fixes. For maximum performance and battery efficiency, regularly check for and apply updates.