pre 6-stars, where to spend Skillpoints?

[t11_fan]

But players growth rate decreases when he becomes scout.
Take screenshot of your training when player has 5* and when he has 6*
Skill progress per lost condition rate changes.

[Cat Harrison]

But players growth rate decreases when he becomes scout.

It might be clearer to say that they slow down when they accumulate enough points to reach the next star. Because even if they aren't applied (unless to SA or Role) they still will slow.

Holding points is only useful if you are detemining if it is worth to put the SA/Role or for contract to be less expensive when renewed.

As khris says sometimes it's better to add an SA or Role to a lower star player as they gain faster, but then of course you need to train a bit extra to add to his overall Quality. That is what I usually do, get a super fast 3 or 4 star to give extras.