Some people literally spend hours in the gym. You've seen them meandering from the coffee machine to the changing room, hanging about chatting in the weights section and milling around the water fountain.
For those of us that like to have a life outside of the gym, it's about getting in and out as quickly as possible, maximising the time you are there.
For speed, some exercises are better than others because they work out multiple areas of the body. It also means you won't succumb to chicken leg syndrome - that guy who's essentially an upper body perched on toothpick legs.
Here HuffPost UK Lifestyle asked our brightest and best fitness experts for their favourites...
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1. Squats
One of those wonder exercises that works you out all over, squats tone your butt, legs and also abs as you have to hold your core tight while doing them.
Charli Cohen, fitness expert and HuffPost UK blogger says: "Back, front, plyometric, single leg, plié, overhead...there are so many variations of this fantastic functional movement."
2. Kettlebell swing
England rugby player and founder of Bodyfire, James Haskell, swears by the kettle bell swing. "The kettle bell swing is a fantastic all around exercise. It’s great for burning fat, developing muscle, increasing endurance and aerobic capacity. It also provides a full body workout, can be performed with very little space required and with just one simple piece of equipment, the kettle bell."
3. Deadlifts
For women, these are fantastic as they burn through body fat. For men, they help build a powerful, all over build as they work your back, legs and arms.
For technique, Bodybuilding.com advises: "The exercise is done by pulling the weight off of the floor and then standing with your legs straight and your shoulders back. To keep pressure off of your spine and lower back muscles it is important to keep your back straight.
"Once you have a reverse grip on the bar (one hand over, one hand under) you want to drive the weight from your heels through your legs. In the down position you want to have your thighs parallel to the floor. You should have your knees directly over your feet. Make sure your knees aren't past your toes or behind your heels. You want to keep your butt low to the ground in the downward position."
"Try alternating conventional deadlifts to work your whole back and straight leg/Romanian deadlifts to target the legs and bum," says Charli.
4. Spiderman walk
"This is an amazing exercise for the abs, arms, chest, back, inner and outer thigh - pretty much all over," says personal trainer Christianne Wolff. "Go into an extended plank position- arms straight hands on the floor, legs straight behind you. Open your hands, then open your legs, then keep doing this walking to the right."
5. Burpees
You will never hear a personal trainer talk bad about burpees even though every person who does them utters a long groan beforehand. The reason why trainers such as Sam Feltham love them is because they work out literally every area of the body.
12 Minute Athlete reports: "Burpees are an intense fully body exercise, they burn a ton of calories. Plus, research shows that high intensity exercises like burpees burn up to 50% more fat than moderate exercising.
"And better yet, they speed up your metabolism throughout the day—meaning you’ll burn more calories all day long, even after your burpee hell is over."
6. Press-ups
"There's a reason they have been around since the beginning of time," says celebrity personal trainer Hayley Newton, "and we all know what they are because the work. I'm a firm believer in using your own body weight to work out with and this is the perfect example. You're not only using your arms but your entire core as you have to hole the plank position throughout, also it's great because you can modify it for people who struggle by putting your knees down."
7. Downward Dog stretch
Personal trainers are fans of all-over-body workouts and downward dog - the formation where you stretch in a V-shape - is one of those stretches. It improves your circulate and is fantastic for the back, but it also strengthens your "hands, wrists, low-back, hamstrings, calves and Achilles tendon."
8. Lunge kicks
If you thought lunges were hard, you haven't experienced a lunge kick. Christianne says: "This is an amazing all-round leg strengthening and toning exercise, and it stops the muscle bulking up, as squats can do. Lunge down and kick your back leg in the air, and then place back down into a lunge again."