The kids are back in school, which can bestow a sense of routine in a household — except when it doesn’t, as when school activities kick into high gear.

Healthy snacks become a lifeline, whether for an out-the-door breakfast, tucked into a lunch bag, or to appease an appetite until dinner.

Granola bars began appearing on grocery shelves in the mid-1970s, often as thin slabs of oats, honey and earnestness. What began as hippie fodder gradually morphed into bourgeois decadence, with bars including chocolate chips and macadamia nuts, corn syrup and marshmallows.

There still are good bars out there, but why not make your own? It’s easy, thriftier and the bars can be customized for everyone in the house. (Individually wrapped in foil, granola bars last a week.)

Better yet, everyone can make their own versions to have on hand.

The basic recipe starts with old-fashioned rolled oats and a sweetener that also acts as a binder. That’s often honey, but other options include brown rice or maple syrup, which also makes them vegan.

Flaked coconut is popular, and you can use the sweetened kind — because it’s delicious, right? But you still can have coconut flavor with less sugar by using unsweetened coconut, available as finely chopped (or desiccated) or in shavings.

Wheat germ boosts nutrition, as do almonds or other nuts, which also provide crunch.

Customization comes to the fore in the choice of dried fruit. You can use any combo that adds up to 1½ cups. Our base recipe, from Ina Garten, calls for dried apricots, dates and dried cranberries. But we played with pineapple and papaya, raisins and mango.

One discovery gleaned from various recipes: Adding a teaspoon of instant coffee (or espresso) powder has a way of tempering the sweetness without making the bars taste bitter, adding a depth of flavor that we really like. But it’s optional.

Ingredients are one thing; execution is another. A crumbling granola bar is frustrating and messy, so take your time when mixing the hot honey mixture into the dry ingredients until all surfaces are evenly coated. Press firmly into the prepared pan; dipping your fingers in water combats the stickiness.

Then, once baked, press down on the bars with a spatula or pancake flipper. Let them cool completely before cutting.

One last thing: You don’t have to go to school to enjoy these snacks.