Dad said yes to changing the locks. Good. That is not yet a locksmith order.
One provider may quote rekeying the existing cylinders. Another may assume full replacement. A third may give a low arrival price and decide what the job costs while standing beside an open door. Those are three different transactions wearing the same work shirt.
Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.
Your job is to make each locksmith price the same result: the same doors open with the agreed key, every old key stops working where Dad wants it stopped, and nobody leaves with vague authority to enter later.
Start with Dad's decision, not your theory
If Dad can make and communicate this decision, the call belongs to him. He chooses which locks change, who receives a key, and whether one key should operate several doors. Being his son does not automatically give you authority to order entry or alter his locks over his objection.
Ask Dad four plain questions: Which doors are included? Which people should still have access? Should the old keys stop working everywhere? Does he want you present when the work happens?
Write his answers on one sheet. If he wants you to arrange the visit, have him join the first call or give the locksmith written permission that names you, the property address, and the work he approved. Ask the provider what identification or proof of occupancy it requires before dispatch. A provider willing to bypass the ownership and authorization question is not doing you a favor.
If Dad is locked out and may be hurt, this is not a quote-comparison exercise. Use the emergency route described in Start Here. Do not turn a welfare emergency into a hunt for the cheapest locksmith.
Separate rekeying from replacement
Rekeying changes the internal keying so an old key no longer operates the lock. Replacement removes some or all of the existing hardware and installs different hardware. Either may be sensible. They should not be priced as though they are the same job.
Before calling, photograph both sides of every included door and the edge of the door where the latch or bolt appears. Count keyed knobs, deadbolts, sliding-door locks, storm-door locks, garage service doors, and any padlocks Dad expects to be included. Note locks that stick, spin, sag, or require the door to be lifted.
Send the same inventory and photographs to every provider. Ask each one to label every line as rekey, repair, replacement, or no work. If replacement is recommended, ask what defect prevents rekeying and whether the quoted hardware changes the way the door locks from inside.
Do not accept "all exterior locks" as a scope. The locksmith and Dad may have different ideas about whether that includes the door from the garage, the basement walkout, the storm door, or the detached garage.
Make the key plan visible
A lock job can be technically complete and still leave the family guessing which key opens what.
For each quote, ask:
How many distinct keys will the house use after the work? Which exact locks will each key operate? How many copies are included? Who is permitted to request additional copies? Are any keys or codes restricted by a manufacturer or provider? Will the locksmith account for every key cut during the visit?
If Dad wants one key for several doors, have the provider confirm that the existing cylinders can be keyed alike. Similar-looking locks are not proof that their cylinders are compatible. If hardware must be replaced to create one-key operation, that belongs in the written quote.
Decide where the copies go before the machine starts cutting. Dad keeps his. Name any second holder. Put spare-key storage in the scope only if Dad has approved it. Do not quietly create a family key ring and call it safety.
Compare the complete visit
Ask for a written estimate that separates the service call, labor, parts, key copies, after-hours charge, and any charge for drilling or difficult removal. Ask what condition would permit the price to change and who must approve that change.
The Federal Trade Commission cautions consumers that paid search results and displayed phone numbers may lead to an impersonator rather than the business the consumer intended to call. Verify the company through its own established contact information, and ask for its physical business name and address before dispatch. That consumer guidance is collected with the desk's other references on the Sources page.
Then compare the providers on the points that matter at Dad's door:
Will the person arriving identify the company before beginning? Will the technician inspect the doors before changing the scope? Is Dad's approval required for added work? Will replaced parts be left with Dad if he wants them? Is labor covered if a rekeyed lock stops operating properly? Who returns for a correction, and what part of that return visit could carry another charge?
A warranty without a covered task is decoration. Ask whether it covers the cylinder, replacement hardware, installation labor, key operation, and the trip back. Get exclusions in writing.
Missouri's Attorney General advises consumers to retain contracts, invoices, warranties, receipts, and communications when a service dispute arises. Build that record while the job is calm, not after a key fails. See the source trail on Sources.
Do not let the doorway rewrite the deal
Before work begins, stand with Dad and the technician at each included door. Match the written scope to the actual lock. Mark any change on the estimate and get Dad's approval before drilling, replacing hardware, or adding a charge.
If the technician says the quoted work cannot be done, ask for the reason in writing and the full revised total. Dad can approve it, decline it, or pay only an agreed service-call charge if the estimate allows that. Urgency at the threshold does not erase the need for a number.
When the work is complete, test every new key in every assigned lock from both sides where applicable. Close and latch each door before calling it finished. A deadbolt that turns while the door is open may bind when the door is shut. Confirm that old keys no longer operate the locks Dad intended to change.
Count the new keys in front of Dad. Write down who holds each copy. Collect the final invoice, hardware information, warranty terms, and the provider's correction number in one envelope or shared file.
The next concrete move
Tonight, photograph every lock Dad wants changed and make a door-by-door list with four columns: rekey or replace, keys that should work, number of copies, and person authorized to approve changes. Send that identical sheet to three locksmiths and ask each for a written, itemized estimate before anyone is dispatched.