How to best teach it?

I struggle with how and when is best to teach someone new stuff. I can teach someone the same thing 2 or 3 times and if I offered to do it a 4th time, they may take me up on it. When does it become enough? I am not saying there's anything wrong with the person OR with what's being taught. I think it all revolves around the willingness to change and the openness to new things on an individual basis. I have worked with my 8 year old on blogging...I set him up a blog, showed him how it works, how to get pics off of his digital camera and helped him post a few things AND STILL he could really care less about blogging. It just isn't important to him at this point in his life. Yes, I see the benefits of starting him young and teaching him the power of writing for an audiance, creating a positive digital footprint, etc. But he just doesn't get it because HE doesn't want to get it or he doesn't see the importance of it. So should I bother? Should I teach him something that he doesn't see as important for his life? OR, should I work hard to teach him the "why" in hopes that he will begin to the see the importance and then take on the challenge of learning something new for himself, making a personal connection to whatever that may be so that it has meaning to him and not just me? I am pretty sure the latter is the better choice. Well, I KNOW the latter is the better method but I often find that I teach something and try planting seeds in soil that isn't ready. All that to say I think there is something to be learned from nature, which is lots of cultivation paired with critical timing is a necessity for proper growth to occur. Trying to facilitate growth when the conditions are not right can lead to discouragement. But being there when all things are aligned is a pretty amazing thing to witness and knowing you are an active part of that is truly indescribable. It's why I teach.