But when you're a vegetarian (as I was), to maintain a reasonably nutritious diet requires some repetition. For example, getting certain protein and nutrients in one meal so you don't have to think about it in the others.
I'm no longer a strict vegetarian (just mostly), but the diet habits I learned mean that my overall diet is better, lower calorie.
I now think it's important for EVERYONE to do strict vegetarianism. Not for ethical or environmental concerns, but simply because it forces you to think about what you're eating and to read labels (and thus learn that the "vegetarian" tacos you're eating have gelatin (meat product) in the sour cream).
In addition, being a strict vegetarian in a sustainable way requires learning about what your body requires.
After a few months (or however long it requires to build a stable, nutritious diet), you'll be extremely well informed. Of course, you could also just read all this stuff on various articles, but trial by fire is an excellent way to learn.