Dad will tell you there are no mice. He will also tell you he heard them in the garage, that he set out a trap, and that the trap is fine. You will find the droppings behind the paint cans before he does. That is the usual shape of this call, and it is why a pest service is worth comparing instead of booking the first truck that answers the phone.
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.
Start with the inspection, not the spray
A company that quotes you before it has looked at the house is selling a treatment, not solving a problem. Ask whether the technician will inspect the garage, the crawl space if there is one, the attic, and the spots where pipes and wires come through the walls. Ask what they will look for and whether they will show you what they found. A good inspection ends with a short written list: where the activity is, what is letting the animals in, and what the company plans to do about each opening. If the answer is that they will see when they get there, keep looking.
Ask what goes on the floor and the walls
You are entitled to know what product will be used and where. Ask for the product name, and ask to read the label and the safety data sheet. Ask whether they have a option that is less hazardous for a household with a cat, a dog, or small grandchildren, and whether they use bait stations, traps, or sprays in the living areas. You do not need to become a chemist. You need to be able to say, plainly, what is going into the garage and how close it sits to the cat's bowl.
Read the return visits and the guarantee
Most of the real work happens after the first visit. Ask how many follow-up visits are included, how soon the company comes back if the activity continues, and whether each return costs extra. Ask what the guarantee covers, how long it lasts, and what counts as a failure. Get all of it in writing. Ask whether the plan is a single job or a recurring contract. If it renews, find the cancellation date before anyone signs.
Compare two or three before you choose
Call at least two companies and ask the same questions in the same order. Write the answers in columns, one company per column, covering the inspection, the products, the return visits, the guarantee, and the renewal. Notice which company answers without changing the subject. Notice who puts the plan on paper. The one you pick should be the one whose written plan you could hand to your father and he could read without you explaining it.
Let Dad stay in charge of the door
He should be home for the first visit, or at least know the technician's name and the arrival window. Many men will agree to a service if they are asked to approve the plan rather than told it is happening. Let him ask the questions he wants to ask. Let him say no to a spray in the kitchen. You are the one who makes the calls and keeps the paperwork, but the house is still his.