I've been reading "Relentless Forward Progress" by Byron Powell for the last few days, and it goes into depth on different training programs and what you should ideally run every day for the next X amount if weeks to run a certain distance. It's got several of these training programs for various race distance goals, and weekly mileage goals.
Looking over these I get overwhelmed. I obviously don't train via any "program" or anything like that. I do use the Maffetone Method, but it does not dictate how often, or how far, I can run.
To me, training should be fun and enjoyable. Once you put it down on paper in a strict regimen with limits and expectations, well... That sounds a lot like work to me. And I don't want work and running intertwined (unless I start getting paid to run!)
So here's my thoughts on a good "training program" that I guess I attempt to follow...
Phase 1; Base Building.
In this phase you aren't concerned with speed or timed PR's, instead your just building up a good solid base of running. The goal is to add more and more miles on your feet and feel comfortable running for multiple hours on end.
Basically a bunch of long slow runs. This isn't to say you can't do some speed drills or run fast, but that this should t be your priority. Running fast is fun! Do it! But I think that building a good aerobic base is the key element to a successful and long term running career.
Phase 2; speed work.
After you've successfully built a good sold base of long slow miles its then time to start working on speed. At this point running for 6 to 8 hours straight should be a walk in the park! So now you need to increase the amount of ground covered in those 6 to 8 hours by being able to run at an increased speed. Don't stop running long slow runs, just don't run as many and start mixing in some faster runs and speed workouts.
Phase 3; races! (Optional)
Now that you can run for hours on end, and you can run them somewhat quickly, its time to put yourself to the test! Get out there, strap a race number to your ass and burn up the trails!
Phase 4; REPEAT!
Since you can run faster, start back with the longer runs at the increased speed until it becomes easy, then go longer! After that, start running faster and then maybe go win a few races!