Nicole Letts is an Atlanta-based journalist with work published by AAA Explorer Alabama, BBC Travel, Good Grit, Southern Living, and more.

Lamps are among the longest-lasting household items. They are easy to repair or rewire, making them instant family heirlooms. You likely have one or two lamps you've inherited from generations gone by (or one or two you've picked up at an antique store). While lamps might last forever, their lampshades do not. Over time, shades might turn yellow, become damaged, or simply go out of style. No matter the reason, the real conundrum is understanding how to select a replacement. Vintage Lamp Harps

When you choose a lampshade, you should be armed with measurements. Anna Louise Carter, decorator and blogger at Designed by Dixon, says, "A general rule of thumb is that the lampshade diameter should be about twice the width of the widest part of the lamp base." Carter says the shade should cover the bulb socket, and no more than one-inch of the lamp's neck should be visible. "The width of the shade is the priority. Once you have that selected, you may need to adjust the harp as needed."

Another detail to keep in mind is the shape of your lamp. "The shape of the shade should mimic the shape of the lamp," says Carter. For example, a round base should have a round shade while a square base should have a square shade. "You can deviate and get creative, but do so with caution," she explains. The most popular shade shapes include, but are not limited to, bell, drum, empire drum, and tapered square, but the list could really continue from there.

Shades come in a variety of materials: linen, silk, and even metal are all commonly used. Fabric covered, pleated shades are having a moment in design. While these types of shades are aesthetically beautiful, the amount of light they allow through is determined by their coloring. A dark lampshade is not going to provide as much light as a white shade. "A dark lampshade also sets a more formal tone," says Carter.

Lamps are used for more than just looks. While they are an important part of decorating, they are an even more important part of a room's function. Besides windows or overhead lighting, lamps are how light enters, exits, and circles a room. Lamp placement, then, is key. A task lamp shade directs light downward and is convenient for a reading chair while a table lamp with a drum shade will provide 360 degrees of light. "Lamps also give a room ambiance and provide a welcoming glow. If you're having company over, you should have every lamp in your room turned on," says Carter.

Large Finials Decoration When in doubt, take your lamp into the store with you, and use these tips as your guide. "So much of getting the lampshade correct is trial and error. It's okay to try multiple before getting the right one," Carter says.