We put a storm door on front and back doors. We have time then to open a door to talk to salesmen, delivery men, mail men etc. through the glass and dogs don't run out. You need to keep a leash by the door and if you need to open the storm door you have time to put the leash on. Be sure everyone in your home is aware and no one leaves a door open or ajar. Maltese is so very small, easily lost, and unable to fend for themselves - we have one. Also a harness is much better than a collar, which they can slip out of.