Dad says the missing key is probably in the junk drawer.
You have looked in the junk drawer. You have also looked in the bowl by the telephone, three coat pockets, the garage, and the coffee can full of keys that apparently belong to every house except this one.
Before you call anyone, decide what problem you are paying to solve. A missing copy does not automatically mean every lock must be replaced. You may only need new keys. You may need certain locks changed so an old key no longer works. Or Dad may want one key that opens the doors he actually uses.
The right choice is the one that gives him a house he can enter and secure without making the doors harder for him to use.
Start with a door and key count
Walk the house with Dad. Let him lead, even if he insists the side door is the front door because that is where everybody comes in.
Write down every outside door, including the door between the garage and the house. For each one, check the knob or lever, the deadbolt, the key that operates it, and whether the door closes properly before it is locked.
Then gather the keys you can find. Test them one at a time and label them. Do not assume matching locks use matching keys. Mom may have had a system that made perfect sense to her and remains completely invisible to everyone else.
This count matters because service calls, the number of lock cylinders, replacement hardware, and extra keys can all change the total cost. A vague request to fix the locks invites a vague estimate.
Know what you are comparing
Rekeying changes the working parts inside an existing lock so the old key no longer opens it. The visible hardware usually stays in place. This can make sense when the locks work well and Dad is comfortable using them.
Replacing a lock means installing new hardware. That may be useful when a lock sticks, the finish is badly worn, the thumb turn is difficult for Dad to grip, or the doors have a collection of unrelated hardware that cannot be made to use one key.
Ask whether the locks can be keyed alike. One house key may be easier for Dad than a ring that resembles a small janitor's collection. But do not pay to match a door he never uses unless there is a practical reason.
What drives the cost up or down
The first cost is getting someone to the house. Ask whether the service-call charge is separate from the work and whether it changes outside normal working hours. If the situation can wait, scheduling an ordinary appointment may cost less than asking for immediate service.
The number and type of locks matter. A door with both a keyed knob and a deadbolt may count as two pieces of work. Patio doors, storm doors, old mortise locks, keypad locks, and locks without an available key may require different labor or parts.
The condition of the door matters too. A new lock will not correct a sagging door, a loose strike plate, or a deadbolt that cannot enter the frame without Dad lifting the handle. Ask the locksmith to separate lock work from door repair in the estimate.
Hardware choice can widen the difference quickly. If replacement is recommended, ask for the price of a plain, easy-to-use lock before considering keypads, remote controls, or other added features. Those features may help, but only if Dad wants them and will use them.
Finally, count the copies. Decide who truly needs a key: Dad, you, a nearby relative, and perhaps one trusted helper. Ask how many keys are included and what additional copies require.
Questions to ask before booking
Tell the locksmith how many exterior doors you have counted and whether each has a knob, lever, deadbolt, or keypad. Then ask:
Can the existing locks be rekeyed? Can the doors Dad uses share one key? Is the service call included in the estimate? What would require additional approval once the locksmith arrives? Are new keys included? Will you test every lock with Dad before leaving? Can you provide an itemized receipt showing labor, hardware, and copies?
Ask for two versions when both are practical: the cost to rekey usable locks and the cost to replace only the hardware that is worn or difficult. That gives you a real decision instead of a single take-it-or-leave-it total.
If the answer is that everything must be replaced, ask which specific lock cannot be rekeyed and why. You are not challenging the person doing the work. You are making sure Dad pays for the house he has, not a standard package built for some other house.
Keep Dad in the decision
Ask which door he wants to use every day. Watch him unlock it, turn the deadbolt, and pull or push the door open. A perfectly good lock on paper may still be a nuisance if the key is small, the turn is stiff, or the door must be tugged into position.
If you are considering a keypad, ask Dad to enter a sample code before buying one. Talk about where the code would be kept and who would receive it. Also ask how the door opens if the batteries stop working. A keypad should remove a problem, not give Dad a new household appliance to argue with.
Do not hide a spare key without telling him. Choose the location together, or give the spare to a person he names. It is still his house.
What to do tonight
Find the key Dad uses now and put it in the place he already reaches for it. Test the door with him from both sides. Make sure it closes, latches, locks, and unlocks without forcing it.
Count the exterior doors and photograph each lock. Put the keys you have found in separate envelopes or attach simple labels. Write down which key opens which door.
If one lock is sticking, do not make Dad wrestle with it tonight. Agree on another usable entrance until it can be checked. Leave the final hardware decision for a calm conversation when you have an itemized estimate.
When to ask the doctor
A misplaced key now and then is ordinary. Ask Dad's doctor about it if losing keys is part of a broader change you have noticed, such as getting lost on familiar trips, repeatedly locking himself out, struggling with other familiar household tasks, or becoming suddenly confused.
Write down what actually happened and when you noticed the change. Bring observations, not conclusions. If the confusion appeared suddenly or Dad seems unwell, seek prompt medical help.
Add this to the good-week card
Every outside door has a working lock, and Dad knows where his everyday key and spare are.