New York City Homeowner's Guide -
Have good locks put on all points of entry. Inspect all doors and windows
for loose locks, deadbolts, hinges and latches, and repair promptly.
On exterior doors, a one-inch deadbolt lock provides good security.
One-inch deadbolt locks on all exterior doors are effective, though
care should be taken when installing double cylinder locks on emergency
exits. Locks that have the keyhole in the knob are a poor choice. They
are easily forced from the outside.
Padlocks should be good quality with heel-and-toe locking. A good padlock
will have a double locking shackle at the toe and heel, a five-pin tumbler
and a hardened steel shackle, the bigger the diameter, the better.
Locks are only as good as the keys that control them. If keys are lost,
change the locks.