A door lock is one of the most frequently used items in the home. You likely turn the lock or deadbolt every time you leave the residence, reopen it when you get back, and shut them for the night when you go to sleep.

But despite this regular wear and tear, we don't often think of door locks as a feature that needs regular maintenance. As a result, homeowners might be caught off guard when a lock suddenly stops working properly.

A few simple maintenance steps can help keep your locks in good condition. You can also keep an eye out for warning signs indicating that the door or lock needs to be adjusted.

Determine how old your locks are. Barry Campbell, writing for Angie's List, says the average lock lasts about seven years.

Perhaps the easiest way to keep a lock in good condition and prolong its life is to lubricate it periodically. The Flying Locksmiths, a commercial security company, says lock cylinders have several small pins and springs which can become stuck or even break if they aren't able to move freely.

Lubricating a lock is an easy process. The Doors Depot, a company in Bayonne, N.J., says you simply need to spray some lubricant into the keyhole, then insert a key and remove it without turning it. After wiping off any dirt that sticks to the key during this process, reinsert the key and turn it a few times to help spread the lubricant.

Graphite or dry lubricants should be used rather than oil-based ones. Peifer Security Solutions, a company in Memphis, Tenn., says petroleum lubricants are more likely to bind up the moving parts in the lock over time.

Lubricating the lock once a year may be sufficient. The Doors Depot recommends completing the process every six months.

Another easy maintenance step is to simply clean the lock. Campbell says a mild detergent, or even just a damp cloth, can be used to wipe dust and dirt off the lock. Avoid using abrasive cleaners or petroleum-based products, which can damage the finish.

Periodically, you can inspect the workings of the door to see if anything is amiss. The Doors Depot says this inspection should check to see that there are no issues with the door frame and that the locks, hinges, and other hardware are all working properly.

Pay close attention to the strike plates and deadbolt. Peifer Security Solutions says an inspection can help you determine if any parts are deteriorating or coming loose.

Ensure that the deadbolt is lining up correctly with the strike plate. Campbell says the bolt should not be hitting the strike plate when closed, and that you shouldn't have to push the door or otherwise alter the alignment after the door is closed for the bolt to fit properly. There should be enough space in the doorjamb for the bolt to enter fully. The Flying Locksmiths says you may need to remove debris from this opening to prevent the bolt from being blocked.

The door needs to be properly hung for it to function properly and to avoid putting undue stress on the lock. The Flying Locksmiths says that if daylight is visible between the frame and door, it's a clear sign that it needs to be repaired. You may also notice that the door is rubbing on the floor when it is opened.

Hinges are also a common source of a misaligned door, as the screws that hold the hinges in place will loosen over time. Tighten the screws up to keep the door from rubbing against the frame and to ensure that the lock will line up correctly.