Locked doors provide a sense of security and calm your mind, but can also be annoying when the key is not working properly. You have to remember, before you start opening the door lock and breaking down the door, you should be absolutely sure that you already have no other choice. After that, you can call a professional locksmith such the ones that you may find on locksmith services to help you fix the door. Else, you may also call the locksmith since the first time you have problems to open your door. But, of course, it will not kill to try opening the door yourself first.
If it is the door of your house which has problems to be unlocked, there are several ways that you can do to help you open your door without a key. You can use some other things to help you and one of them is a card. If your door has a simple key system, you can try opening it using a credit card. This simple trick is getting more and more ineffective on modern doors, but still useful when you want to get into the house with the old model door when you forget to bring the key.
Laminated cards usually work better. You need a fairly flexible card for example, a shopping card that you no longer need. You should know that sometimes this card can be damaged by the process of opening the door, so it cannot work anymore.
To try opening the door with the card, you need to slide the credit card in the gap between the door and the sink. Then, move the card down behind the latch.
After that, slowly but surely, you can pull the card toward you while turning the doorknob. If you are lucky, a credit card will slide in the gap between the slanted side of the key latch and the hole on the door frame, so you can push the latch out of the frame by pulling the card toward you. To keep the door open, place the card in the slot between the latch and the keyhole. Of course this trick will not work if the door is locked from the inside using a latch.