They should also be rekeyed whenever the door lock key is lost or stolen. Your apartment key should be on a separate ring from your car key. You may possibly use a detachable key ring. Never place anything on a key ring that indicates your apartment or address. Never attempt to hide your apartment key outside the apartment.
Burglars know the hiding places.
For sliding glass doors, install a horizontal locking bar. A broom handle in the track at the bottom of the door can serve the same purpose. If the sliding glass doors can be lifted from its track, install two screws backed with a stack of washers at the top of the track. The screws should protrude downward just enough that the top of the door clears them. In apartments, windows are the second most favorite points of illegal entry.