When I run, I enjoy running how long I feel like running... how fast I feel like running... when I feel like running. I have these guidelines that I put on myself that I more or less follow. With these guidelines, I have the general idea of what I'm going to do. Sometimes, mid-run, I change my mind and I go off and do something else. Although my running may seem somewhat random, there is some sort of purpose with each run I have. The hardest part about my running is that sometimes, I become lazy and think to myself, "Tomorrow, I'll run long, so today, I won't go too hard." and start off my run like that. However, what tends to happen is that I would change my mind and decide to work harder or run longer and tomorrow decide how my run would turn out to be.
In giving myself the freedom to choose my own workouts and how much I do, I give myself a potential of an unlimited amount of running. Usually, because of my passion towards running and the yearning I have to become better, I tend to push myself just hard enough that I run further and get better. The thing about letting go of my limits and following how I feel is that it allows me to grow further than I would have, had I limited myself to a certain sort of work out. A set workout will control your growth, however, it limits your growth to your plans, not allowing you to stretch further.
My idea of unlimited running only works if you're mentally prepared to push yourself as much as you are able to after understanding yourself. Most people who start running shouldn't do this because most of the time, they won't feel like running and will be more likely to skip work outs because they'll try to deal with themselves. However, there will always be the exceptions which will do just fine with this sort of training. In actually understanding the concept of unlimited running, you will be able to push yourself as far as you can without hurting yourself.
Being able to put yourself through the unlimited training, and you can perform amazingly. In order to improve yourself, it's all about not having any limitations that keeps you from performing at your best. At times, things we set out to do pushes us too much... and at times, it pushes us too little. Only in pushing ourselves enough do we improve the most effectively. Find that point where you can improve at your best, and push forward.
(today, I did a 3 mile warm up, then 800 meters at 80-85 sec per lap, then a 400 meter jog. I repeated that 4 times altogether, and then did a 3 mile cool down. It was nice to push myself on that 800 meter... my original plan was to run 400 meters hard and take a break and repeating that. Finding out that I could go beyond that and enjoy it as I pushed myself, I changed my mind mid-run)