Choosing the right door lock for your door is a process that takes into consideration your security needs, the style of your door, and your home's aesthetic. Lock Type : One of the most important factors to consider is whether you need a mortise or a cylinder lock. A mortise lock sits into a space on the edge of the door and is secured by a horizontal bolt that sits just within the door frame. A cylinder lock sits into a circular hole on the edge of the door that is cut usually by a power saw. The cylinder lock is the most popular choice.