GFCIs (ground fault circuit interrupters) are the electrical outlets in your house that protect you from electrocution by cutting off the power when they detect a disturbance in current. They’re found anywhere you have running water — the kitchen, the bathroom, the garage, etc. — and they have two buttons: test and reset. Test your GFCIs once a month by plugging a small lamp into each one and pressing the test button. The button should click, the light should go off, and the reset button should then pop out. Press it and the lamp should come back on. Any other result means the GFCI has failed or your outlet is wired incorrectly; call an electrician for help.

If you ever come home to a flooded floor, you need to be able to shut off the water to the whole house ASAP, especially if the source of the water leak is unclear. That’s why every homeowner should know where her main shutoff valve is — and every home is different. Look near the perimeter of the house at ground level nearest your water meter. The shutoff valve might be in a basement, crawlspace, closet or garage, but should never be covered over with drywall; look for an access panel or hose bibb. In an emergency, you can also shut off your water from the outside water meter, but the valve might require special tools to turn. 

If you’re hanging a picture or shelf, you need to be able to locate a wall stud to nail into for support. You can always shell out the 20 bucks for a battery-powered stud finder, but Frank Lesh, owner of Home Sweet Home Inspection Company in Indian Head Park, Ill., also recommends another tool: a bright flashlight. Start by locating an electrical outlet along the wall, since the receptacles are typically fastened to one side of a stud. Studs should be located every 16 inches or so, although your mileage may vary. “Tap on the drywall,” Lesh says. “It should sound hollow as you move to the left or right. As the sound changes, that indicates where the stud is. If you have a really bright flashlight, point it alongside the drywall and it will show any imperfections. If you find a string of indentations, that’s where nails are — that’s the stud.”

A healthy tree is a lasting asset to your property, but unfortunately, planting properly is a task that many homeowners get wrong. The rules are different depending on whether you’re buying a tree bare-root, in a container, or balled and burlapped, so read up at the Arbor Day Foundation before you grab a shovel and start digging. Some cardinal rules: never bury the root collar under soil (that’s the part where the roots join the trunk), don’t pile mulch on the trunk (the ubiquitous “volcano” look smothers roots and rots bark), and don’t fertilize after planting (it can kill young trees).

Your refrigerator works hard around the clock, so maintaining it properly is crucial to avoiding repair bills. Dirty coils make the fridge work much harder than it has to, shortening its lifespan, so cleaning them periodically is a good idea — especially if you have pets, whose shedding hair tends to pile up underneath the fridge. Pull out the fridge from the wall, unplug it briefly while you work, and locate the coils, which are either on the back or underneath the fridge behind the front grille. Vacuum the coils with your own attachment or a coil cleaning brush (available at hardware stores).

If you’ve got tile flooring, tub surrounds or backsplashes, you’ll eventually need to clean the grout if you want them to stay beautiful. Go easy, though — grout is less durable than the tile it’s holding together, and harsh cleaners like bleach can erode it. Start with water and a stiff brush, and if that doesn’t do the trick, try an oxygen cleaner or a mix of baking soda and vinegar followed by brushing. Deep stains may call for replacing the grout altogether.

There’s really no need to hire a professional to do this — you can get great results yourself if you follow a few simple guidelines. Top tips: use good tools, don’t skip a thorough wall prep and work from the ceiling down so that you can catch mistakes.

It’s important to schedule a maintenance checkup for your HVAC system every spring and fall, but in the meantime, filters need to be checked once a month. When they’re dirty, change them; dirty filters shorten the lifespan of your system. Fortunately, it’s easy to do. First, check your owner’s manual for the right part number in order to buy a new filter. Then turn off your HVAC system while you work, remove the old filter and slide the new one in place.

You probably put a lot of miles on your lawn mower every summer, so to keep it running properly, an oil change at least once a year is in order. Changing the oil involves disconnecting the spark plug so the engine won’t start, draining the oil into a pan designed for that purpose (and taking it later to a recycling center), replacing the oil filter and refilling the oil. Tractor Supply Co. offers a complete how-to.

Front-loading machines are a great water saver, but they have a dark side: smelly mildew buildup that can infect every load you run. To prevent this in the first place, use high-efficiency detergent only, and use as little as possible (only one to two tablespoons per load, believe it or not). But if the mildew has already appeared, there’s no need to buy a specialized cleaner. Just run your unit’s cleaning cycle if it has one, or run an empty cycle using hot water (no soap) and put bleach in the dispenser. Afterward, wipe out both the gasket and the front door and dry thoroughly. Repeat periodically as needed.

When you need to hang something heavy in a place where there’s no wall stud for support, drywall anchors are the way to go. When you install them, the barbs on the end of the anchor fan out behind the drywall, providing the needed support. The simplest drywall anchors are self-drilling; use a screwdriver and apply steady turning pressure until the edge is flush with the wall, and then insert the screw for hanging your items. Other types of anchors require you to pre-drill the hole.

When gutters get clogged, water can be trapped on the board behind the gutter and even be forced under your roof shingles, causing damage. So clean twice a year in spring and fall (and be mindful of ladder safety as you work). Start near a downspout by removing large debris, and then use a hose to flush a stream of water through the downspout to clear out fine grit. If your downspout is blocked, it may need to be removed and cleaned out; if it leads to an underground pipe that’s blocked, that pipe can usually be cleaned out with a handheld snake.

If you come home to standing water in your basement, time is of the essence. “You have 48 hours to get the water out and get it dry,” says Frank Lesh of Home Sweet Home Inspection Company. “After two days, mold will start to grow, and once that starts you have to rip everything out.” Call your insurance agent right away and take pictures; then get to work pumping out the water and removing all furniture to be dried off. Important: make sure the power is off if there’s standing water! As long as the water is below boot level, Lesh says, you can safely shut off the power from a basement panel if you wear rubber boots and gloves and use a wooden stick or hammer handle to trip the main power switch.

Take the time to get to know your attic space. “Most people don’t go up there enough,” says Steve Gladstone, owner of Stonehollow Fine Home Inspection in Stamford, Conn. “Things can get bad quickly if you’re not paying attention.” He recommends visiting during a downpour so that you can see if anything is leaking. Make sure your attic vents are open and look for signs of moisture and mold — silver-dollar shaped marks on the floor or insulation are telltale signs you’ve had condensation. Also look for animal droppings, torn or slipped screens over vents, cracked or sagging rafters, and exhaust fans venting into the attic instead of outside. A last tip: “Make sure you’re standing on wood, by the way, and not the pink stuff,” Gladstone says. “I’ve had clients disappear.”