It’s possible, but depends on the design of your lock. Some door locks that lack a keyhole do boast a small hole on the exterior handle or knob. This hole’s primary function is to allow water to drain out of the lock, in addition to giving homeowners an easy spot to insert lubrication. However, you can typically use a paperclip in this pinhole to unlock the door by manipulating the mechanism inside. 

The best type of deadbolt depends on your specific needs. If accessibility is your primary concern, a single-cylinder deadbolt is the easiest to operate. Mortise locks are likely the most secure type of deadbolt you can install, but single-cylinders combined with secondary locking mechanisms like vertical locks are also a great option. Smart locks will give you the most flexibility to open and close your locks whenever and wherever you need to. 

You might assume that having two locks on one door will offer more protection than only one lock, but there may not be an advantage. While there’s nothing wrong with having two locks if you feel it’s best for your living situation, rest assured having one high-quality deadbolt installed correctly will offer a high level of protection.

Yes, with better technology now available, it’s possible to add a smart lock on your sliding glass door. Smart locks can be easy for almost everyone in the family to operate and can connect to other safety features in the home, like smart lights. Plus, they’re harder for would-be criminals to pick. However, keep in mind that smart locks can potentially be hacked, and some completely rely on phones or Wi-Fi, which can be an issue if the power goes out.