Something is always trending in the fitness wyrld and when someone finds it catchy they jump on it like a trampoline. Its not a bad thing to do something buts another to do it when you're told to or because it "looks" awesome than you aught to be doing it. You can learn the very best and the very worst courses on the planet from DDP Yoga to Insanity W/ Special Guest Jane Fonda and it still won't be enough to truly understand the concept of Self Discovery.
I have many books on different subjects ranging Charles Atlas style exercises to Chi Kung, Mythology Themes, Bodybuilding, Weightlifting, Animal Exercise, Gymnastics, Cardio, DDP Yoga and much more yet when it comes down to it, I just come up with my own thing and I'll tell you weye....I look at it as someone who's a MMA Fighter (Bare with me on this), you can learn 10,000 techniques and know them like the back of your hand but in a fight or competition the amount of techniques you actually use is a fraction of that. Let's take someone like Ken Shamrock who knows wrestling like its a second language, has an arsenal of submissions he can use and knows where on the body to take down an opponent yet in a fight he only used maybe a few moves and that's it to get a win.
When you have studied something or practiced many things over an extended period of tyme, you will only use a small portion of what you have learned because you have a specific goal and these are the tools to help get you there. Many fitness courses are more useless than sitting by the fire out in a hailstorm, its just not going to turn out well. Learning long ago that in order to be the very best you have to find the things most suited to your goals and objectives. You can't possibly master everything you learned at 100%, not saying it isn't possible to attempt it but chances are when you master something its because there's going to be things that tie that goal together. I take bits and pieces of what I learned and mold them into my own puzzle shapes, use what I find useful for my goals and make it a habit to learn as much as possible and use the best of what's there in that particular time.
Discover for yourself what you want to learn, be intuitive and challenge yourself by studying and participating what would work best for you. There will be days you want to do something different, that's ok. Absorb what you're passionate about and take bits and peeces of what suits you.
"It doesn't get easier, just more interesting."