It decreases weekly for all players. The higher the level of the skill the faster it decreases (ie it takes fewer weeks to go from 9 to 8 than from 2 to 1).
If I were you I would only train stamina in 'shorter' weeks, like ASG week (next week) or the final week (you only have 3 games if you play a Finals tiebreaker). Stamina and FT are not affected by age (or very little) while it becomes impossible to train other skills after a certain age. This is why people normally leave ST and FT last when training players.
What everybody said here above about higher stamina being good is true, however 3 or 4 ST is already a decent level where you don't have to worry about your player playing badly despite great skills.
Last edited by Lemonshine at 11/9/2017 11:11:24 AM