When you open your eyes first thing in the morning, you probably don’t spend much time deciding whether to hop in the shower or check your phone. Whatever you’re used to doing, that’s what you do. In many ways, you’re operating on autopilot.

These rise-and-shine routines and countless other automatic or nearly automatic behaviors are your habits. They encompass everything from the way you answer your phone to the foods you reach for in the grocery store. And you should be grateful for them. Without them, your brain would buckle beneath the weight of the countless small decisions life throws at you.

“If we all had to deliberate about every little thing we do in each moment, we wouldn’t be able to function,” says Phillippa Lally, a psychologist and senior research fellow at University College London. “Habits free up our brains to be thinking or concentrating on more important things,” she says. Habits, in other words, are evolutionarily programmed efficiency hacks.

Making new habits

Lally has published several studies on habit formation. She says that habits are largely the product of deeply entrenched pathways in the brain, which themselves are firmly strapped to environmental cues. When you climb into your car, for example, the familiar sights and sounds of your automobile lead you to put on your seatbelt or plug your phone into its charger. There was some time in the past when these actions weren’t rote; you had to think about them and decide to do them. But now they’re automatic. Research has found that circuits in the brain that control habitual behaviors may actually compete with those circuits that control more deliberate, “goal-directed” behaviors.

“To make a new habit, you need to repeat the same behavior in a consistent setting,” she says. This “in a consistent setting” element is crucial. If you don’t anchor your new habit to a specific contextual cue — such as during your train ride to work, or just after you finish doing the dishes at night — it’s unlikely that you’ll stick with it. If you’re trying to read more books, say, both of these times each day could be good anchors for that new habit. More research has shown repeating behaviors in this way helps form habits through the involvement of multiple brain regions.

Predictable situations make the best new-habit cues, says Benjamin Gardner, a habit researcher and senior lecturer in psychology at King’s College London. So let’s say you want to do yoga twice a week. Rather than trying to fit in a yoga class whenever your schedule allows, make a plan to go every Tuesday and Thursday immediately after work.

It’s also helpful to map out the nitty-gritty details of your hoped-for behavior. If you want to get more fruit in your diet, make your goal to eat exactly 10 raspberries every morning with breakfast, or to have an apple every day with lunch. “The more specific and clear your plan is, the more likely you are to follow through,” says Gardner.

In the beginning, he says that simply forgetting about your new goal or behavior is another big hurdle. Maybe you had every intention of going to the gym after work, but then the night before you forgot to pack your workout gear. “Setting lots of reminders or alerts is a good idea,” he says. You could schedule one reminder the night before to pack whatever gear you need, and then other reminders leading up to or just before your new behavior.

It’s unclear just how long it takes for people to form a new habit. Gardner mentions an old myth that doing something every day for 21 days will solidify it. In reality, he says, it could take many weeks or months for a new behavior to become truly habitual — meaning you do it without thinking about it. But on the bright side, most behaviors start to feel familiar and less-effortful after just a few weeks, he says.

Breaking old ones

While forming a new habit is no walk in the park, breaking bad habits is often much trickier. “Once a mental association is there, it’s really hard to remove,” UCL’s Lally says. Maybe you’re accustomed to pouring yourself a drink when you walk in the door after work. Or you spend every night on your couch watching Netflix when there are other things you should really be doing.

It can help to adopt a new behavior to replace the unwanted one. Rather than simply trying not to have an alcoholic drink when you walk in the door, you could make a plan to drink your favorite Kombucha every night when you get home. Or if exercise takes away your urge to drink, you could go for a short run every night. “You’re trying to associate the situation” — in this case, walking into your place at night — “with a new, better behavior,” Lally says. (Worth noting here: If you’re concerned that a frequent behavior may turn into a bad habit, varying the times and places when you engage in it can prevent that from happening in the first place.)

But maybe the best way to break a bad habit, Lally says, is to change or avoid the environmental cue that triggers your unwanted behavior. “When you move to a new place or job, that’s a great time to form new habits because everything’s different,” she says.

If that sort of large-scale change isn’t possible, smaller switches can also help. For example, if dumping sugar in your coffee is a problem, going to a new coffee place should make it easier for you to form a new routine. Even minor environmental changes can be helpful. “Maybe you’re trying to drink less dairy, but you still need to keep some milk in your fridge,” Lally says. “Putting the milk in a different place can slow you down and help you remember that you don’t want to drink it.”

Finally, attaching rewards to new behaviors can work wonders. “If you try to create a habit you don’t enjoy, it probably won’t work,” she says. But if you can imbue that new habit with something enjoyable — a tactic Lally calls “temptation bundling” — that can improve your odds of adopting it. Maybe there’s a blog or podcast you really dig. Let yourself read or listen to it only while you’re at the gym on the elliptical. Over time, your brain will start to associate that activity with the thing you love, and you’ll find yourself looking forward to your gym time, rather than dreading it.

Habits aren’t easy to make, and they’re often even more difficult to break. But with proper planning, you can do both.