Whether you’re a cardio fiend looking to sculpt stronger muscles or just trying to get back in shape, pretty much any personal trainer will point you in the same direction: strength training.

Building lean muscle helps you move more easily through everyday life, improves your posture, and supports bone density—which is especially important as you get older and your muscles and bones naturally weaken. And, of course, there’s everyone’s favorite muscle benefit: It boosts your metabolism.

“If weight loss is a goal, having more lean muscle will help you burn more calories,” says Albert Matheny, M.S., R.D., C.S.C.S., co-founder of SoHo Strength Lab. Plus, strength training also regulates hormones (for both men and women), which can boost your mood and sexual health, he adds.

Related: 6 Ways Building Muscle Benefits Your Health And Well-Being

But with so many ways to approach strength training, it can be hard to figure out how many of your workouts should be strength-focused, which muscles you should hit each time, and how long you should spend in the gym. Whether you do full-body lifts or split up your workouts bodybuilder-style for different muscles depends on your goals—and how many hours a week you’re willing to log in the weight room. We got the scoop from the experts, so you can figure out which strength-training method is best for you, and start seeing results.

Full-Body Strength Training

Who it’s for: If you’re looking to maintain your general fitness or get back in shape, total-body strength training is a good foundation. “It’s great both for people who aren’t in the best shape and for anyone who wants to get the most out of their time,” says Matheny. “Full-body training boosts your overall health, burns calories, and makes you less prone to injury.”

What it involves: To make the most of full-body training, you’ll need to work out for 30 minutes to an hour, starting with two or three training sessions a week, suggests Matheny.

In everyday life, you aren’t plopping down on a machine and doing a leg press or bicep curl—so full-body strength training sessions focus on multi-joint movements, in which you work the muscles you need to move, balance, and stabilize your body in the real world. “Total body workouts focus on the bigger muscle groups and involve more than one muscle group in an exercise,” says Erica Suter, C.S.C.S. Think squats (core, hamstrings, quads, and glutes); deadlifts (core, hamstrings, glutes, and back); pullups (core, back, and biceps); and bench presses (core, triceps, and pecs).

Because you’re working all the muscles, give yourself at least a day of recovery between full-body strength-training sessions at first, says Suter. You might lift on Monday, Wednesday, and Friday, or on Tuesday, Thursday, and Saturday, for example

In each workout, you’ll choose one total-body movement, like the squat or deadlift, to be the main focus of your training session. You’ll dedicate between one and five sets of one to five reps to this main lift. Then, follow that move up with a few additional movements that also work major muscle groups, like dumbbell rows, reverse lunges, pushups, and farmer’s carries. Pick up to seven of these moves, called ‘accessory lifts.’ For these, perform three to four sets of eight to 10 reps.

If you plan on doing any cardio on the same day as your full-body strength training, save it for after, so you can strength train with full energy and power.

Related: 3 Ways To Improve Your Deadlift And Crush Your Next PR

Each of your workouts for the week should be slightly different, says Matheny. So, if the main lift in your first workout hits your lower body, choose an upper-body main lift for your second workout. Same goes for your accessory lifts. If you did a bunch of lunges that first workout, swap them for hinge movements (like single-leg deadlifts) the next workout. Even if you just slightly vary the exercises you do—like performing lateral bodyweight lunges instead of barbell reverse lunges—you can boost your results and keep from getting bored, Matheny says.

You’ll want to stick with these workouts for about four to six weeks, says Matheny. Throughout that time, slowly decrease the number of reps you perform and up the weight you lift so that you’re progressively building strength—especially in those main lift movements. After four to six week, switch things up and pick new moves to work on.

At that point, most people are able to tack on an additional day of strength training, says Suter. Just keep in mind that varying the exercises in your workouts is especially important if you’re doing full-body strength training on back-to-back days, Matheny adds.

Bodybuilding

Who it’s for: Bodybuilding is more about achieving a certain ‘look’ more than it’s about improving your overall health and fitness or losing weight. “The goal is to sleep, eat, and train—and limit other exercise in order to get big and cut,” says Matheny. This training style is best for people with specific aesthetic goals who are ready to commit over an hour to the gym almost every day.

What it involves: Pro bodybuilders work out up to 10 times per week, but you can transform your physique with about four or five lifting sessions a week, says Suter. You’ll need at least 45 minutes to an hour per workout. Many bodybuilders just lift, so all of their workout efforts maximize muscle gain—but to maintain or improve your overall fitness and cardiovascular health, you’d want to add in a session or two per week of longer-duration, lower-intensity cardiovascular training (like jogging for an hour), says Matheny.

On a bodybuilding-style training plan, you’ll perform exercises that isolate one specific muscle at a time (like doing skullcrushers for triceps), or that hone in on a specific pair of muscles (like doing lat pulldowns for lats and biceps).

Because each workout is hyper-focused on just a couple of muscles, your training days may be broken up as follows: On Monday you train back and biceps, on Tuesday you train quads and hamstrings, on Wednesday you train chest and triceps, and on Thursday you train hamstrings and glutes. From Friday through Sunday you’ll either rest or do a second training session for any of the muscle groups you really want to bulk up.

In each lifting session, you’d perform about 12 to 14 exercises to really laser in on and exhaust those muscles. On a back and biceps day, that might mean a bunch of variations on bicep curls and back rows in which you switch up your equipment (dumbbells, barbells, resistance bands, and machines), and how you perform the move (hammer curl versus classic bicep curl, or overhand grip versus underhand grip). For each exercise, you’d perform three to five sets of eight to 15 reps using moderate weight and work to complete fatigue.

If you incorporate weight machines into your workouts, meet with a trainer once or twice when you get started to ensure your form is correct so you don’t hurt yourself, Matheny says.

To boost the muscle-building effort you’re putting in at the gym, be sure to bump up your calorie intake, since getting enough calories is key for packing on muscle and size, say Suter. You might want to sip on a protein shake during your workout, she says.

Follow up your lifting sessions with a few minutes of stretching to keep those just-worked muscles from tightening up like crazy.