As I practice competitive programming more and more (and thus implement more and more algorithms), I've begun to have somewhat of a worry that I'm developing the bad habit of favoring recursive implementations over iterative ones. I've mainly implemented DFS/DP/Backtracking recursively this far, and that has made those methods of implementation come much more naturally to me. However, pretty much all study material recommends iterative solutions over recursive ones for the lower constant factors they usually have. This has made me wonder if it would be worth pushing myself to think of the iterative implementations instead of the (to me, more intuitive) recursive ones when solving problems. Has the difference in complexity between the two ever made a difference in competitive programming contests? What about outside of the CP scene? In working environments where efficiency is a major concern, are iterative solutions generally that much better than recursive ones?

I've often heard the advice that you should take notes after any difficult problems, writing down the Eureka that helped you solve it, or even after learning anything new in general. However, I personally struggle immensely with actually taking down notes, so I wonder what other, more experienced programmers' experience is with note-taking. Do you actually find it helps you maintain your knowledge and keep track of important points, or is it unnecessary in your opinion? Primarily, I want to know if it's worth it to push through my difficulties and force myself to take notes. Importantly, I'm not talking about writing in general--I'm well aware of the usefulness of thinking through a problem with pen and paper. I'm specifically asking about note-taking for future review or even just for the boost to memory you get by writing it down (etc. etc.).