Locksmith in Kent GardensAfter a break-in,the door comes first

Frozen cylinders open well with patience: lock de-icer or gentle warming melts the ice so the plug turns, and the cylinder is then dried and treated with a dry lubricant that sheds moisture. Hot water is avoided because it refreezes and can crack cold metal. To prevent a repeat, keep a storm door closed over the main lock, fit a keyhole cover on exposed side doors, and carry a small de-icer in your coat or car through the freeze-thaw months.

It usually points to the mortise case rather than the cylinder, and it is a common complaint on commercial doors. Inside the case a return spring, a worn hub, or another part of the latch's drive path can have failed, so the lever moves without driving the latch. The locksmith gets the door open, draws the case out of the door edge, replaces the worn part, cleans and greases the contact points and refits everything, then tests lever, key and thumb-turn together.

It is good practice whenever a key has been out of your hands for a while and you are not certain it came back. Contractors, cleaners, sitters and short-term guests all have honest reasons to hold a key, and most return it, but a rekey at the end of the arrangement is what turns 'probably' into certainty. Some households make it a habit at the close of every project.

Not a problem, just a detail to plan around. What matters is the keyway, meaning the profile of the slot the key fits, rather than the name on the lock. Different makers sometimes share a profile and sometimes do not. Where two cylinders cannot accept the same key, one is exchanged for a compatible cylinder in the same finish and pinned to match. From the outside the door looks the same and from your pocket it is one key.