The popularity of Korean-style barbecue is partly a function of the main courses themselves—the beef, chicken, pork, or fish that are marinated, seasoned, and seared to perfection. But that popularity owes at least as much to the delectability of the accompaniments known as banchan—the side dishes that enable each diner to create a meal that suits his or her own preferences. These small bowls of kimchi, shishito peppers, stir-fried mushrooms, condiments, and sauces provide an object lesson in the power of customization. If desired, guests could go without having exactly the same meal twice.

The thrill of discovery, the desire for flavor adventure, and an overall insistence on having it their way are defining elements of the millennial palate. These qualities, of course, pose special challenges for quick-serve and fast-casual chains, whose business models traditionally were predicated on uniformity and assembly-line efficiency. But if anything has become clear since I last addressed the topic of customization in this space four years ago, it’s the fact that the drivers underlying the do-it-yourself trend have, if anything, come to exert even greater influence over menus nationwide.

Here are the four “DIY drivers” I identified in 2013. Considering how quickly food trends come and go, it’s astonishing how resilient these phenomena have been. And that staying power suggests it’s worth operators’ time to consider different ways to address the customization craze.

1. Fresh is forever.

Once people come to appreciate the power of fresh ingredients, it’s hard for them to revert to items that are frozen, canned, vacuum-packed, sealed in jars, or dehydrated. And the fact that large fast-casual chains such as Chipotle and Panera have made fresh ingredients their brand signatures has only raised the bar for other concepts.

Today, consumers of all ages value both the taste and the appearance of fresh ingredients. We see manifestations of this trend throughout the restaurant world, most recently in the form of ceviche and poké restaurants, such as the Santa Monica, California, outlet Sweetfin Poké, where diners can select from bases such as bamboo rice or kelp noodle-cucumber slaw; top them with yellowfin tuna, salmon, snapper, or albacore; and finish off the works with a range of sauces and vegetables. My Ceviche, with multiple locations in Florida, takes a similar approach, with fresh raw fish that can be prepared in several types of citrus-juice concoctions.

As I’ve said for years, if you can’t actually make it in-house, source ingredients that are of high quality and that telegraph “fresh,” such as pickles, olives, or seasonal condiments. The resulting freshness halo will resonate with discerning, quality-minded consumers.

2. Transparency.

Another driver of the do-it-yourself trend is transparency. Operators today need to be proud of their ingredients and keep those ingredients front and center.

A little theatrical flourish can come in handy here. At Amazebowls in Los Angeles, açai bowls, smoothies, and other superfood treats can be customized with toppings that are laid out along the counter so customers can appreciate the freshness and variety of the offerings. This allows for endless customization, with the consumer assuming the role of chef/cook.

Similarly, at Asian Box locations in California, the emphasis is on what the concept calls “farm-to-box street food.” “From sauces to marinades to dressings, our dishes are all made from scratch and capture the authentic flavors of Asian street-food carts in a modern box,” the chain’s marketing materials boast. “Our customizable menu puts customers in full control over their dining experience.” Those boxes are built around bases ranging from brown and jasmine rice to rice noodles and Asian salad, with proteins, fresh bean sprouts, and jalapeños, as well as fresh sauces, all tossed into the mix in a presentation that’s ingredient-focused and fresh.

3. Flavor.

Today’s consumers demand bold flavors, but “bold” isn’t necessarily synonymous with “spicy.” What they want are assertive, distinctive, and memorable ingredients—condiments, sauces, herbs, spices, and so on—that take a position and stick with it, whether that position is spicy, bitter, sour, or sweet. Operators can address this demand by supplying guests with a broad array of do-it-yourself additions—culinary oil paints that allow them to customize their canvas to their liking.

4. Diet-friendly.

Operators today need to be able to cater to a myriad of ever-shifting diet trends. Gluten-free, vegan, vegetarian, dairy-free—the list continues to grow. And the reason dieters are worth indulging is that they often represent the veto vote when it comes to restaurant selection. This is where salads can shine. It’s far simpler to offer consumers the ability to compose their own salads than it is to construct separate menu categories for each set of dietary restrictions. And by offering a broad range of greens, grains, proteins, vegetables, nuts, seeds, and fruits that can be mixed and matched at will, operators can ensure that no dieter’s needs go unmet.

Each of these four drivers have only gained momentum as local restaurants, grocery stores, take-out joints, and food trucks find new and better ways to allow consumers the freedom and flexibility to design their own meals. Time and again, guests have shown they want customization as an option. DIY isn’t going away; chains hoping to capitalize on personalization will do well to explore different ways to give consumers more say in how they construct their menu items.

This story originally appeared in QSR’s March 2017 issue with the title “The DIY Challenge.”