First and foremost, write your code so that it can be understood easily by someone that knows nothing about it. As you get older, you'll realize that this person is you! Anything written over 2 weeks ago is often like looking at new code, so make sure you have good comments and non-obscure variable names so that you can understand it easily. This also makes it easier on your coworkers. Second, write for readability a…
Sorry, but actually it sounds like quoted from a (programming) fantasy novel. Look at the other comments, who argue that the nice and clean code is not always the best, not always the goal and sometimes not even a goal that can be achieved. This(!) is what you learn from experience.
The time difference between writing clean code and crappy code is negligible. The main difference I saw was always in the attitude of the programmer. This is what you really learn from experience. There are lots of programmers out there with diva complexes who think it's beneath them to write easy-to-understand code, or love using 1-character variable names, etc.
Sure, maybe there might be situations where you don't have a lot of time, for example, if you are programming algos for HFTs and the traders are standing over you yelling that they need a particular parameter changed and they are losing a thousands of dollars per minute.
But in most other situations, it doesn't take much time to type "ptrCache" vs "ptr1", or add comments so that the next person who reads your code won't be scratching their head wondering wtf you were thinking.