So you’re a first-time buyer who just closed the deal on your new home and moved in. Finally, you can breathe a deep sigh of relief. After all, you managed to pony up a down payment, closing costs, and other sundry expenses. Provided you make your monthly mortgage payments, you’re fine and dandy on the finance front … right?

Not quite. Because owning a home means you have to maintain it—and maintenance costs money to do right. Expenses that you may not have considered are bound to crop up after you’ve bought the house. Some are one-offs, but others will come back around regularly. Overlook them at your peril, since neglect may just lead to even bigger breakdowns that will cost you more down the road.

Want to know what lies ahead? (Hey, it’s better than being blindsided.) Check out these hidden expenses that first-time buyers often overlook.

1. New locks

Cost: $100 to $350, plus installation

Once you’ve signed on the dotted line, you get to take the keys to your new home—but before moving in with all your stuff, you should get those locks changed ASAP.

“I don’t think people are thinking about who else has a key: the babysitter, dog walker, mother-in law,” says Elizabeth Samti, a real estate agent for Weichert Realtors in Cherry Hill, NJ. “People aren’t conscious about how many keys could be floating around out there.”

2. Tree trimming/removal

Cost: $75 to $4,000, depending the height of the tree

You remembered to budget enough to purchase a lawn mower and an edger, or maybe you set aside money to pay for a lawn maintenance service. But did you remember tree maintenance? Many first-time home buyers don’t, and if your property has older trees on the grounds, tree trimming or removal can cost a pretty penny.

For instance, having a tree completely removed can average $4,000 or more. And if you want that pesky stump removed, too, expect to cough up several hundred more.

3. HVAC maintenance

Cost: $70 to $100 twice a year

Twice-a-year maintenance on your HVAC system can prevent expensive emergency repairs in the future. Even brand-new systems need check-ups, as most warranties require regular maintenance.

The cost of HVAC maintenance depends on the payment plan you select. If you choose to pay a technician each time he comes to your home, you can wind up paying up to $100 per visit. Instead, Samti recommends signing up for a yearly service contract. These contracts typically include two check-ups a year, and may also offer perks like priority emergency service or a small discount if repairs are needed. The price of a year-long contract depends on its terms, but tends to run around $150.

4. HVAC filters

Cost: $10 to 25 a month

Also on the HVAC note: “The whole system works better if you change your filter once a month,” says Samti. Basic filters won’t break the bank, but filters with allergy reduction elements typically have a higher price tag. To save money, Samti suggests buying filters in bulk or subscribing to a monthly filter delivery service, which will drop a filter right at your door when it’s time to be changed.

5. Duct cleaning

Cost: $450 to $1,000, depending on the size of the home

If you purchase a previously lived-in home, contaminants in the ducts can be a major problem for allergy suffers. Samti recommends paying for a one-time duct cleaning in homes where the previous owners had pets, especially cats.

The National Air Duct Cleaners Association points out that the duct cleaning cost for an average-sized home varies depending on a number of factors, such as the number of ducts, level of contamination, and environmental factors.

6. Fire extinguishers

Cost: $20 to $75 per extinguisher

In some states, home sellers are required to keep a fire extinguisher within 5 feet of the kitchen when their house hits the market, so there’s a chance there will be one waiting for you when you move in. But if your newly purchased home doesn’t include a fire extinguisher, Samti suggests buying at least one to store in the kitchen.

7. Smoke/carbon monoxide detectors

Cost: $12 to $80 per unit

New homes usually come equipped with modern smoke and carbon monoxide detectors that are hardwired, but previously owned homes may contain older, battery-operated detectors that are way past their prime. In addition to replacing any outdated detectors, Samti recommends installing smoke detectors in every bedroom in your home—even if they’re not required by law.

8. Pest control

Cost: $50 to $250 for initial treatment

Even if you paid for a pest inspection before purchasing, you can still end up with an army of ants marching across your kitchen counter in the spring. An initial treatment to exterminate ants can cost $50 to $75, and your exterminator will typically charge around $40 for each additional month he needs to continue treatment, according to Ed McGettigan of Exterminating Company of America in Audubon, NJ.

As for rodents, the cost depends on how many critters are crawling around your home.

“Since there are various methods of removing rodents, the fees for each method will vary, but expect to pay at least $75 for an initial visit from any pest control company,” McGettigan says.

9. Fireplace cleaning

Cost: $75 to $175 depending on the length of the chimney

If you purchase a previously owned home that includes a fireplace, you’ll need to pay to get both the fireplace and chimney cleaned. While a home inspector visually inspects the chimney’s structure, he’s not a specialist in its cleanliness, according to Samti.

“Even if you think you’re not going to use it, get the fireplace cleaned,” she says. “It’s such a fire hazard. You have no idea how long stuff has been in it.”

Robin Shreeves is a journalist, a Level 3-certified sommelier, and the founder of wineandwonder.com. She’s the wine columnist for the Courier Post, and a food and drinks writer for Mother Nature Network. She co-wrote “The One Year Women in Christian History Devotional.”