As part of regular maintenance, you need to evaluate how external and internal door locks work. This will enable you to provide complete care and to get timely fix, if it is necessary. The condition of locking devices is best evaluated with two methods. The first one is visual inspection and the second one is testing. Find out how to test these devices correctly and to identify any problems that affects them.
Wiggle the handle a bit while the door is locked - You simply need to hold it and move it up and down slightly. Another option is to slap the handle from below. You must not use too much force, however.
Assess the performance of the handle based on movement - When you apply a bit of force to the handle it should move slightly. This motion can be very limited. If the handle is completely stuck and you actually feel opposing force, there may be a problem with its setting. You should opt for timely door lockset fix to avoid dealing with an emergency problem later on.
Slip the key into the keyhole gently and evaluate its movement - This test is necessary for determining the condition of both the door lock cylinder and the key. Move the key slowly and pay attention to the contact between it and the keyhole.
If you feel that the movement of the key is obstructed, you need to clean the keyhole to remove any foreign objects. Apply vacuum or compressed air first. Then apply graphite lubricant directly into the keyhole. Keep doing this until the compound that comes out is completely free of foreign particles.
If you hear scraping sounds or you simply feel the two metal surfaces rubbing against each other, inspect the key for damage and more specifically for chipping, denting and bending. If any damage is present, timely key repair is required.
Turn the key to lock the door - Do this slowly while applying pressure only in forward direction. You should never apply pressure to the side as this can easily lead to breakage. Notice how smoothly and quickly the cylinder moves.
Lubricate the locking device if the test shows that it is sticky - Clean it first and then apply lubricant. Spread a tiny amount of the lubricant around the front section of the device for best results. If this basic solution does not help and the device keeps performing poorly, lock repair will be needed.
Do not procrastinate getting repair if you notice any problem that cannot be resolved with basic means. Leaving things as they are will most certainly make the condition and operation of the locking device worse and you may end up in a dire situation like lockout all of a sudden.