Depending on the door lock and style, you may have to remove the knobs to replace the lock. In some cases, there may be a set screw under the knob, and you can remove it with an Allen key.

Because it doesn't replace the entire deadbolt, a retrofit is usually less expensive. Expect to pay about $30 to $50 less for a retrofit compared with a completely new smart locks.

Replacing door locks. The most comprehensive method of ensuring security, door lock replacement involves removing the existing lock from the door (including the handle if it’s a handle-lock ...