I want to continue this discussion a bit; I'm from Finland, and want to give an example of the training of our national steeple record holder (8.10,67), 2006 European Champion Jukka Keskisalo. He is born in 1981 like I, and we have raced in the same races few times. He went from 8.16 to 8.10 in one year, in 2009 when he was 28 years old. He had trained hard for years at a high level, but felt like he needed to change things a bit and a former Finnish 5-10k runner (13.21/27.53) Risto Ulmala started to coach him. Tommy Ekblom, a 8.19 steeplechaser from the -80ties created the base. Ulmala was 7th at the 1991 WC 5k held in Tokyo, just behind Khalid Skah.
The most significant change was based on the fact that Keskisalo wasn't improving anymore and struggled at the steeple/3-5k pace. He had been done 10 years of training at slower than race pace during winter in his hardest workouts (close to VO2max), doing the fartleks, moderate runs, a weekly 10k tempo (well over 30min), hills, easy mileage, aerobic threshold runs, etc. It had increased his aerobic capacity to a very high level, improving still on the workouts but not showing it in the races. What could he do? Ulmala simply made him increase the pace of the VO2max-type repeats towards closer to race pace, and in order to be able to do it succesfully and in a repeatable way, they increased the recoveries between the repetitions. They also dropped the mileage a bit. The hardest weekly session was 6x1k with a recovery that enabled him to finish the session. The years before he did slower VO2max-type workouts, with more volume, and using shorter recoveries. Like 8x1k or 4x2k. So he had the base / aerobic capacity to successfully move towards better "quality", more race specific workouts. He kept the weekly 10k tempo in his schedule.
They did also some changes to his racing calendar and altitude training during the season. In the following summer he ran his PB's at 1500 (3.38,90 from 3.42,6), 2000m (5.00,32, national record, from 5.07 in the previous year), 3000m (7.49,05), 5000m (13.39, from 13.56 done in April 17th that year) and smashed the 33 years old Finnish national steeple record by 2 seconds in Zurich, august 28th. The previous record holder was Tapio Kantanen, who ran 8.12,6 in the Montreal Olympic final in -76, finishing 4th. Keskisalo did also a 8.12 steeple in Monaco in July, and was 8th at the WC's (8.13), he was sharp all the season.
So in 2009 he was able to develop his massive base; aerobic capacity, to a better specific endurance; aerobic power. I said to my wife back then, right after the unbelievable season, that hopefully they understand that after a long season like that, including a lot of high level performances, they have to go back again towards less specific work, with more mileage during the winter, in order to regain the base again. Well, he changed his coach because the Finnish sports union didn't want to pay a decent wage to Mr.Ulmala, and he stopped the coaching. Things went wrong and Keskisalo never was able to go nowhere near of the level where he was in 2009.
The youngsters, distance runners would often be better to emphasize the good, increasing mileage at various paces, for YEARS than worrying about the 1k repeats etc. But are they willing to do the work, with a progression that keeps them healthy? It demands patience, believe in the system, and you have to love the process, the training. At some point you can't increase the mileage anymore, then it's just a matter of keeping the progression going by changing the emphasis as needed. So it's impossible to say what every runner should do, but a good training is greatly about avoiding the mistakes. It demands a lot of thinking about the past, what has been done, what you could add/change, to keep the progression going. You have to see the big picture. And take the rest, when needed. Good night.