Sight, smell, taste, touch, and sound. All five of our senses have the power to trigger thoughts or feelings of the past and bring memories back to life. Nostalgia is defined as a sentimental longing or wistful affection for the past, typically for a period or place with happy personal associations—and it often scores big with consumers when used as a marketing technique.

Big brands know there’s something to be said about connecting consumers to their pasts. Jack Daniels, Microsoft, Toyota, and Apple are just a few brands that have leveraged the power of nostalgia. Toyota, for example, is using The Muppets in its upcoming 2015 Super Bowl spot. Jack Daniels used footage of Frank Sinatra to promote its “Legend” campaign. And Apple hit nostalgia hard this year with its touching Christmas ad featuring a granddaughter using Apple technology to dub a duet with her grandmother’s old records.

Ads that use nostalgia are meant to trigger feelings of comfort, familiarity, and fondness. This technique works especially well in times of uncertainty, when it’s comforting to look back on easier times. But marketers have to be careful. There is a fine balance to the art of nostalgic marketing.

Nostalgia is a bittersweet emotion. While it often evokes feel-good thoughts in our consumers, it can also make them painfully aware that they can never return to those times in their lives. This thought should be in the back of our minds when using nostalgia, but research has shown that in general, this has not had a negative effect on consumer responses to ads.

Like any marketing technique, nostalgic marketing needs to be thought out and carefully planned. You must pay attention to the age of your target audience. Baby boomers and 20-somethings will have different nostalgic triggers. And you have to be sure your topic is old enough to have nostalgic value.

If you’re looking for a fun marketing campaign this new year, try looking into the past. Ads you’ve previously used can trigger some awesome memories for your longtime consumers and spark curiosity in your new ones. If your business has a history to share, let your audience be a part of the fun. Give the good ol’ days some life again.