Personal experience says that pounding yourself day in and day out gives you good results for 2 or 3 years and then you it backfires once you've plateaued and keep trying harder to break it.
Once you've developed your initial base speed, it may be smart to back off a bit.
Agree?
But then there's the need to keep your body is proper form physically. That can only be achieved off lighter training by making intelligent choices regarding nutrition.
Hard to say, but I have found that long term training can generate residual fatigue that seems to respond to a good break of 6 weeks to 2 months.
I have come to learn there are methods to address cycling training stress to ensure consistency of training response such as modulation of the 2 week weighted average of exertion around the 6 week weighted average. Look up "training stress balance" for further details.
I have found that chronic exposure to volume over long periods(9-12 months), does seem to be predictive of performance in the months following and that during that period a reduction of volume has generally no effect on performance.
I had been frustrated that during higher volume periods I experienced very little change in performance. Seems the ratio of stress accumulation to fitness becomes exceeded and following this up with a break produced breakthrough performances.
Seems the careful implementation of stress and recovery is the most significant aspect to all training. The best methods for this are debatable and likely there may be many ways to design a program with this in mind.
I will conclude by saying that some stress will have short recovery cycles, but others are much longer. Being mindfully of the long term and short term stress recovery cycles perhaps gives an individual the greatest leverage for success. Good luck!
Cycle through your training and take a week or two very easy between blocks