On one end I have students who cannot find the time to play, yet at the other end I have to rein in some of their enthusiasm. Quite an interesting job being a chess trainer, right?
Dealing with inactivity is tough - much depends I believe on not just the interest of the student, but the number of activities he/she has. I had just lost a student because he just had too much homework to have any other spare time to rest, let alone play. Recent studies about children aged 4-10 suggest that they are not getting enough sleep (recommended 11 hrs a day for younger kids and minimum 10 for those 8-10). Will this development take its toll on the child's development? I bet it does. Flooding a child's time of a day with tuition, homework etc simply does not give him the necessary time to reflect, ponder and internalise what has been taught. Hence it is through regular, purposeful playing that the assimilation of chess knowledge takes place. Spending hours dishing out chess moves without a clear thought process in my opinion does more harm than good.
For over-enthusiastic players, I would recommend that they work hard on acquiring the thought process of analysis and evaluation by going over master games, learning how decisions are taken and why. This process helps greatly in the understanding of the game and would trump over x hours of playing. I am a firm believer of having some ideas in your head when playing rather than using the trial-and-error method of learning. It is little wonder that many including Botvinnik advocated spending only time for 60 games a year and spend the rest of time preparing. I must quantify that this applies mainly to a professional chess master. For children, a good run of 6 tournaments a year, with ample preparation in between, should suffice. It is not practice that will make perfect, but the correct application of knowledge well ingested that will yield results. Otherwise, we end up perfecting our bad habits which will take a longer time to unlearn!