Locksmith in ChurchillOlder homes.
Original locks, still working.

It can be. A cylinder that is worn, a strike plate that has shifted, or a latch that no longer seats squarely will all produce repeat lockouts even though the key looks fine. The locksmith checks the alignment of the door and frame, tests how smoothly the latch throws, and looks at wear inside the cylinder before simply letting you back in. If the hardware is the cause, fixing that during the same visit is usually quicker than calling again next month.

Yes. Those cylinders let an owner change the key with a small learn tool, but only while a working key is in hand. Without one, a design such as Kwikset SmartKey is removed and placed in its own reset fixture, returning it to a blank state; other cylinder types are rekeyed by their own method instead. A new key is then set and the lock goes back on. It is a few extra minutes rather than a replacement.

As many as you ask for, cut on site from the fresh pinning and tested in each door they should open; two or three is typical for a household. More can be cut later. When you do, bring one of the locksmith's originals to be copied rather than a copy of a copy, since every generation strays slightly from the intended depths. If any key is a restricted type, additional copies come from the record kept for that system rather than from a hardware store.

The lock hardware is the same; the door construction changes the method. Steel and fibreglass doors have a wooden or composite block inside the lock stile, and existing bores are used wherever possible. Where a new deadbolt must be added, the locksmith drills with a jig and bits suited to the skin so the hole is clean and square, and fits an edge plate designed for that door. Insulated doors also move less with humidity, so alignment tends to hold well.