Good questions, let me give my perspective. I go to the gym almost purely for strength training (lifting weights), not cardio, so I'll focus on that. Here are r

Good questions, let me give my perspective. I go to the gym almost purely for strength training (lifting weights), not cardio, so I'll focus on that. Here are reasons to go to a gym to lift weights (no order, but the last reason is the most important): 1. Strength training can be a good way to get fit, as far as I know. It's probably worse than cardio in terms of developing things like your lungs and basic ability to run for an hour. But from the little I know, I'm pretty sure it's a good way to be healthy, which is many peoples' goals, and that's what most people mean when they talk about being fit. 2. Another thing lifting weights does is make you stronger. This is useful, as being strong is good for many things in life. Arguably, this is more useful in "day-to-day" life than being able to run a long time, as you're actually lifting and moving things pretty regularly. (e.g. moving furniture, if you have a child then lifting/playing with the baby, etc). 3. Strength training makes you bulkier, and therefore look better. Or at least some people think so, to some degree. As another commenter said, this is an aesthetic thing. 4. Lastly, and most importantly, people are different. Most people, IMO, don't consistently do a sport they don't like. One lesson I've learned in life is that, if you want to e.g. get fit, the best thing you can do is find something that gets you fit, and that you enjoy doing. So efficiency/cost of the sport here isn't the most important consideration, it really is enjoyment. And enojoyment is, again, a personal thing, just like some people like playing the flute, some like pianos, and some like guitars. (And some prefer to draw, which is free, or to do photography, which can costs tons in equipment).