Why does my battery run down too quick

@olumideadeyemi you are not giving us a lot of history here :-). It would be good to know what you have checked. A rapidly draining battery can be caused by software and apps. Make sure that you check your settings. Remove and/or turn any App off that you do not use. Check your network settings. Make sure that your phone is not consistently trying to search for a network etc. Same with push notifications etc. turn those off as well. Also, check for any software update for your phone. You can usually do that in the Settings menu

The other thing to consider is the battery itself. IF the battery doesn't take a full charge (it can even say fully charged on the phone) it will drain rapidly due to degradation. In that case, you want to go ahead and replace the battery. After that, re-evaluate your phones power performance.