[Thrax]

I've been looking around to research this myself the last few days as I was interested about training & potentials for my own career mode.

While there are some differences in opinion, almost everyone seems to agree that too much training can be bad for getting well-rounded players.

The common analogy is that potential is like a container (e.g a cup or bucket). Every time you train something it adds to the container, filling it up, and once the container is full then no more growth can occur. So if you train all the trainable (mostly technical) attributes, there will be no room for the un-trainable (mostly physical) attributes to grow.

Suggestions seem to fall into two camps:
- Train slightly (e.g. up to XX overall, commonly either in 60-70 range or "first team ready" at lower clubs) then let the rest grow naturally to keep things fairly balanced.
- Don't train at all and let growth happen naturally. Sometimes supplemented by the idea of training when they near their potential to shape the top end of their stats to your liking.

After reading everything I personally like the idea of the second no-training method. In the real world players seem to hit their peaks in their mid-to-late 20s, which the natural growth in game should replicate.