How long does it take to gain skill?  The amount of time it takes is dependant upon the age of the athlete, and the type of skill being practiced. 

Here's a real basic guide to some age ranges, and how long athletes can focus on one particular skill without going crazy or making you (the coach) crazy:

8 and unders: 7-12 minutes
9-10: 10-15 minutes
11-14: 15-30 minutes
15 and up: 30 minutes+

These are rough estimates of course, but the point is that each group of athletes (in particular the young ones) have:

1) a time limit before they lose their focus, and
2) an amount of "skill practice" time that they require to actually acquire the practiced skill. 

If we instruct for too long on one particular skill, the athletes are going to get bored -- and oftentimes begin to practice the skill poorly.  But if we are too brief with our instruction the athletes won't get enough time to focus on skill acquisition.  Finding the right amount of "skill acquisition" time for each training group is a huge part of effective coaching!

Photo Credit: Connor Spielmaker 2011