If a piece of wood furniture is varnished, can I just paint right over it?

No. You’ll need to remove the furniture’s waxy, shiny coating first or the paint will bubble and peel, says Nancy Krass of Atlantique Furniture Restoration in Huntington Station, NY. To take off the varnish, sand it with coarse sandpaper (150 grit), followed by a finer paper (220 grit). For furniture with intricate carvings that sandpaper can’t reach, use a paint-and-varnish stripper like Citristrip ($20 for 1/2 gallon, homedepot.com), then finish with fine sandpaper. After all the varnish is gone, you’re good to go — just wipe off the sandpaper grit with a damp rag, prime the piece, and paint.

How is a perennial plant different from an annual plant?

Annuals are one-and-done plants that live for only a single season. Perennials live for at least three years, and their flowers grow back and bloom each year. The most eye-catching, easy-care gardens are a mix of both, according to Susan Littlefield, horticultural editor for the National Gardening Association. “Perennials should form the backbone of your garden, with annuals adding color in the lulls between perennial bloom periods,” she says. Talk to an expert at your local garden center to determine a good year-round mix for your area.

Do I really need to find a stud when I’m hanging something on a wall?

If what you’re hanging weighs more than 75 pounds, yes. “Studs are the vertical wood framing within interior walls. They’re spaced 16 inches apart, and they can support more than drywall or plaster can,” says Josh Temple, host of HGTV Dream Home 2016. For a heavy TV or mirror, Temple recommends using at least two consecutive studs so the weight is distributed evenly.

I want to replace a ceiling fan with a light fixture. Will I have to install all-new wiring?

Think of this as an even exchange. The wiring is exactly the same, and the swap is simple, so you can do it yourself if you feel comfortable. How easy is the switch? “You’re really just matching wire colors — white to white, black to black, and green to the grounding wire,” says HGTV’s Josh Temple. If there are more wires than you need coming from the electrical box after you connect the new light, don’t panic — just cap those with wire nuts.

Can I increase water pressure in a shower without demolishing walls and installing new pipes?

Maybe. First unscrew your showerhead and remove the restrictor, a disc with tiny holes that limits water flow to about 2 1/2 gallons per minute, says Matt Muenster, host of DIY Network’s Bath Crashers. Clean out any built-up gunk. If that doesn’t do the trick, test how forcefully water flows into your home with a water pressure gauge. (Attach the gauge to an outdoor spigot. You’ll get an accurate reading for the entire house.) Pressure normally ranges from 40 to 85 psi. If yours is lower, a plumber can install a water pressure booster, but be prepared for a hefty bill. If the psi reading is normal but the pressure still feels too low, your pipes may need replacing. As a short-term fix, swap your showerhead for one built to optimize low pressure, like the Reaction model ($25, speakman.com), which helps concentrate a trickle into a powerful stream.

How do I know if I have plaster walls or drywall?

“If your home was built in the 1950s or later, you probably have drywall,” says Matt Blashaw, a carpenter on HGTV’s Ellen’s Design Challenge. Drywall began replacing plaster in the 1950s because it’s faster and easier to install. Also, it won’t crumble like plaster does, so it’s easier to hang items from drywall. To figure out what you have, Blashaw suggests the pushpin test: Try pushing a thumbtack into an inconspicuous spot on the wall. It will go right into drywall, which is soft, but it’s nearly impossible to push one into a plaster wall.

Can any kind of metal pan go in the oven?

Pans made with stainless steel or hard-anodized aluminum are almost always oven-safe. If your pan is nonstick, has a ceramic interior, or has a silicone or plastic handle, it may also be oven-safe — but only up to a certain temperature. That temp is usually around 350°F to 400°F, which means the pan shouldn’t be placed under the broiler. “Extreme heat will warp the shape of certain pans and break down the nonstick surface,” says Eric Hills, associate manager of public relations and consumer engagement for Calphalon. Check the pan’s care instructions or call customer service to find out the highest temperature the cookware can withstand.

What’s the difference between mold and mildew?

Both are fungi that thrive in moist environments, such as in bathrooms and on windowsills. “Mildew refers to mold that’s growing flat in its early stages, like on a shower curtain liner. It’s a milder issue than fuzzy black mold on an untiled bathroom ceiling,” says Steve Moran, board member of the Institute of Inspection Cleaning and Restoration Certification. You can kill mildew and light mold growth with a solution of 3/4 cup of bleach to 1 gallon of warm water. But call a pro for heavy mold or any growth on porous surfaces, like drywall.

If I cut a tulip, will it bloom again in a couple of weeks?

It won’t. Tulips bloom only once a season, so you’ll have to wait until 2017 to see petals again. But if you cut a tulip incorrectly, there’s no guarantee it’ll even come back next year. To ensure repeat flowers, “snip just the stem and only one or two leaves, leaving plenty of foliage for the plant to feed itself,” says Sara Bendrick, host of DIY Network’s I Hate My Yard.

How do I know if a sofa will fit through a doorway?

“It’s all about the sofa’s diagonal height and diagonal depth,” says Joe Zeolla, owner of Z Brothers Furniture Service in Thornwood, NY, a company that specializes in solving stuck-furniture situations. Start by measuring the height and width of your doorway. Next, measure one side of the sofa from the bottom left corner to the top right corner. That measurement — the diagonal depth — needs to be smaller than the width of the doorway. Then stand behind the sofa and measure the frame from the bottom left corner to the top right. That measurement, the diagonal height, has to be smaller than the doorway’s height. Otherwise, it will be tough to get the sofa in, even at an angle. Remember that some sofa legs are removable, which can help. Worst-case scenario: You can have the sofa cut by a pro, who will de- and reconstruct it with no signs of surgery. Just keep in mind that doing so is pricey and may void any warranties.

Is engineered hardwood real wood or fake wood?

It’s real wood, but it’s not solid wood. “Think of engineered wood as a multilayered wood sandwich,” says Scott Humphrey, CEO of the World Floor Covering Association. Unlike hardwood flooring, in which each plank is milled from a solid piece of wood, a plank of engineered hardwood is made from a glued-together stack of thin, lesser-grade wood that is topped with a slice of higher-quality hardwood. While engineered hardwood can sometimes cost as much as solid hardwood, it does have two advantages over the traditional stuff: It’s easier to install, and, if it’s top-notch quality, it can be more durable.

When I’m buying a throw pillow insert, should it be the same size as the pillow cover?

To get a plumped, catalog-perfect look, “buy an insert one size up,” says Jonathan Orr, vice president of product development for West Elm. The extra stuffing offers better support, so the pillow will stay upright. Don’t go larger than that or you’ll risk ripping the seams of the cover. Orr recommends inserts filled with down alternative instead of down ones, which can be too squishy.

What keeps my upper kitchen cabinets mounted to the wall?

Two words: cabinet screws. They attach the cabinets securely to the wall studs, allowing them to easily handle the added weight of all your dishes and glasses. Unlike ordinary screws, this heavy-duty hardware is longer, sharper, and made of hardened steel, says HGTV’s Matt Blashaw. While most upper cabinets never budge, they are at risk of falling if your contractor didn’t use cabinet screws, used the wrong size screws, or didn’t hang the cabinets from studs.

Can I sharpen a serrated kitchen knife?

A serrated knife can be sharpened, but if you look after it properly, it won’t need to be. Every few months, perform routine maintenance: With a round or tapered honing rod (included in most knife sets), just push any bent points on the knife back into alignment. “Do that and you should never need to get a serrated knife sharpened,” says Michael Garaghty, executive chef at cutlery maker Wüsthof. You might be able to run a serrated knife through a knife sharpener’s polishing or stropping function to realign the points, but check the sharpener’s manual first.

Can I replace a chipped tile in the middle of my kitchen floor?

You'll need a tile and flooring expert with an oscillating tool and an abrasive grout attachment to remove the grout and tile pieces, then pop in a new one. After a 24-hour drying period, the pro will come back and apply an extra layer of grout to finish the job. Prices vary depending on where you live, but I'd budget around $200 for the project.

How do we keep our windows from fogging up in the winter?

Condensation on the inside of windows could mean your house is too humid, and a dehumidifier will solve the problem. If that doesn't work, it may mean air is leaking in around the glass. Buy some window glaze at the hardware store and apply it to the edges of the windows to create a seal. If you have wooden windows, the frames may have cracks, and a simple paint touchup will likely fix the leak.

What do I do about a broken doorbell?

Doorbells are pretty simple devices, but they're also mini electrical appliances that should be handled carefully. First try flipping your fuse breaker the problem could be just a blown fuse. If the doorbell still isn't working, turn off your power, then unscrew the switch plate and check to see if the two wires behind it are connected tightly; you may need to adjust them. Still not hearing a buzz? It could mean there's no power running to the switch. Time to call in an electrician for the fix so you don't risk getting shocked or burned.

I'm tired of my bathroom sink faucet. Is it easy to install a new one?

This looks like an easy job, but it's actually deceptively cumbersome, so I'd leave it to a plumber. He'll have to turn off the water and spend about an hour disconnecting and reconnecting the supply lines before he can actually install the faucet. And if the plumber says the supply lines look worn, it's a good idea to replace them while you have help on hand.

My dresser has one tricky drawer that won't pull out. Help!

It's probably the drawer's slides that are sticking, and if they're metal, a little spray lubricant like WD-40 will help things run more smoothly. If the slides are wooden, friction could be causing a binding effect. Remove the drawer and examine all of the slides, both on the drawer and inside the dresser, for any pieces that are broken or splintered. Lightly sand those areas, then finish with a coat of beeswax